<PAGE>

                                                                     EXHIBIT 4.5

                             LESSEE CHANGE AGREEMENT

                          (CONTRACT NO: HU ZI NO. 0713)

Lessor (Party A): Zhang Ling

Original Lessee (Party B): Shanghai Qianjin Culture Communication Co., Ltd.

Guarantor (Party C): Qianjin Network Information Technology (Shanghai) Co., Ltd.

Current Lessee (Party D): Shanghai Cheng An Human Resources Co., Ltd.

            On March 11, 2005, Party A, B and C entered into Building Lease
Contract (Contract No: Hu Zi No. 0311), in which Party B agreed to lease Party
A's office premise at the eighth floor, 755 Weihai Rd, Shanghai.

            Party B, Party C and Party D have together delivered a request to
Party A that, beginning August 1, 2005, the obligation of original Hu Zi
Contract No. 0311 (hereinafter referred to as the "Original Contract") shall be
transferred from Party B to Party D and Party D, on Party B's behalf, shall
perform the terms, obligations and duties of the Original Contract.

            Party B and Party C shall be liable for Party D's performance of the
duties and responsibilities of the Original Contract.

            Having considered the good cooperation between the Parties, Party A
has agreed to the above request from Party B, Party C and Party D.

            Before July 20, 2005, Party D paid rent of 307330 yuan for the month
of August and Party A has provided an official receipt. Party D has given Party
B a deposit on the lease of four hundred thousand yuan. Party A has received
Party D's deposit and has returned Party B's deposit. At the same time, Party B
has returned Party A's receipt for the deposit and Party A has provided Party D
with a new receipt.

            Other than the above amendment to the Original Contract, all other
terms of the Original Contract are unchanged and in force under law.

            There are eight counterparts of this amendment. Party A, Party B,
Party C and Party shall each hold two counterparts.

Lessor (Party A):  Zhang Ling

Legal Representative:

Original Lessee (Party B):  Shanghai Qianjin Culture Communication Co., Ltd.

Legal Representative:

Guarantor (Party C): Qianjin Network Information Technology (Shanghai) Co., Ltd.

Legal Representative:

Current Lessee (Party D):  Shanghai Cheng An Human Resources Co., Ltd.

Legal Representative:

                                                   Contract Date: July 2005

                                       1
<PAGE>

                             BUILDING LEASE CONTRACT

                          (CONTRACT NO: HU ZI NO. 0311)

Lessor (Party A): Zhang Ling

Lessee (Party B): Shanghai Qianjin Culture Communication Co., Ltd.

Guarantor (Party C): Qianjin Network Information Technology (Shanghai) Co., Ltd.

            Party A, Party B and Party C hereby enter into this Contract with
respect to the leasing by Party B of the building premise that Party A may lease
legally after reaching an agreement through consultation on the basis of
equality, willingness, fairness and good faith, and in accordance with Contract
Law of the People's Republic of China and Rules on Leasing of Buildings in
Shanghai City (hereinafter referred to as the "Rules"). Party C acts as Party
B's holding company and shall be liable for Party B's performance of the duties
and responsibilities of this Contract.

            Section I. Details of the Building to be Leased:

      1.    As the title owner of such premise (see Annex 1), Party A hereby
            enters into a lease relationship with Party B. The building premise
            and auxiliary facilities to be leased to Party B by Party A (see
            Annex 2, the area within the red lines) is located at the eighth
            floor, 755 Weihai Rd, Wenxin Newspaper Plaza, Shanghai. The as-
            measured floorage of such building premise for private use is
            2192.06 square meters and public use is 734.9 square meters for a
            total floorage 2926.96 square meters. The premise, in connection of
            usage, is a building premise used for office work, and, in
            connection of type, is an office premise. The structure of the
            premise is _______.

      2.    The areas for public use or sharing, conditions and requirements are
            subject to the rules of the property management. Party A has clearly
            informed Party B regarding the conditions of existing decoration,
            auxiliary facilities, and equipment.

            Section II. Purpose of the Lease

      3.    Party B hereby covenants to Party A that such leased premise shall
            be used as office space, and that it will not perform any illegal
            activities. Party B will not use the premise for purposes other than
            as set forth above without the written consent of Party B and the
            approval by relevant authorities.

      4.    The leased premise cannot be used for the production, storage or
            sale of chemical, explosive and poisonous products.

            Section III. Leased Building Premise Transfer Conditions

      5.    Party A and Party B or their representatives agree that the signed
            building contract includes the following Annexes: Annex 2, the area
            of this leased premise is within the red lines of the building
            layout; Annex 3, a schedule detailing existing decoration, auxiliary
            facilities, and equipment; and Annex 4, a schedule beginning meter
            readings of water, electricity and gas use. By its signature, Party
            A transfers the premise to Party B. At the end of this Contract,
            Party B shall return the premise to Party A according to the
            conditions of Annexes 2 to 4.

      6.    The premise returned by Party B shall be under a condition after
            ordinary use. It shall be inspected and accepted by Party A. The
            water, electricity and gas in the premise returned by Party B shall
            be under a condition after ordinary use. When the

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            premise is returned, the Parties shall sign the inspection form and
            the Parties shall settle with each other payments of the expenses
            for their own account.

            Section IV. Lease Term and Due Dates

      7.    Party A and Party B have agreed that Party A shall deliver the
            premise to Party B by March 15, 2005. The term of the lease shall
            begin on March 15, 2005, ending on December 31, 2006. The rent for
            the period from March 15, 2005 to May 14, 2005 and the management
            fee for the period from March 15, 2005 to March 31, 2005 shall be
            exempted and act as in incentive to Party B to execute this
            Contract.

      8.    Where Party B needs to renew the lease of such premise, Party B
            shall deliver a written request to renew 60 days before the expiry
            of the term of the lease, and, when agreed by Party A, enter into a
            new lease contract with Party A under the same terms with priority
            given to Party B.

      9.    If Party B does not need to renew after expiry of the term of the
            lease, Party B may return the premise to Party A before expiry. The
            Parties shall complete the formalities for the return of the premise
            and all items shall be removed from the premise before expiry of the
            term of the lease. Party B is responsible for the breach of
            contract. If Party B returns the premise later than the term of the
            lease, unless Party B is not responsible for the delay, the penalty
            shall be two times of the monthly rent as stated in this Contract
            and Party B shall be responsible for trash removal fees.

            Section V. Rent and Payment Terms

      10.   Party A and Party B have agreed that, the rent per day per square
            meter of the floorage of this premise shall be (RMB) 3.5 yuan,
            excluding property management expense per day per square meter of
            the floorage of 1 yuan. Party B shall pay directly Party A rent of
            307330 yuan each month. Property management expenses shall be paid
            directly to Wenxin Property Management Co., Ltd. in accordance with
            the rules of Shanghai Wenhui Xinmin Property Management Co., Ltd.

      11.   Before March 14, 2005, Party B shall pay Party A rent of 481485 yuan
            for the period from May 15, 2005 to June 30, 2005. Starting April,
            each month's property management expenses shall be paid directly to
            Wenxin Property Management Co., Ltd. The full portion of next
            month's rent shall be paid before the 20th day of each month. In the
            case of overdue payment, after Party A has provided the written
            payment invoice and payment has not been made within five days,
            Party B shall pay two times of the rent according to the number of
            days overdue

            Section VI. Deposit and Other Expenses

      12.   Party A and Party B have agreed that, Party B shall pay a deposit on
            the lease of the premise of (RMB) 400,000 (four hundred thousand
            yuan). Party A shall issue a receipt certificate to Party B upon the
            receipt of such deposit.

      13.   Upon the termination of the lease relationship, after Party A
            inspects the premise to the conditions of the transfer in the
            Contract and all rent and related expenses are paid in full, Party A
            shall return the balance of the deposit without interest to Party B.
            If there is damage or irregularity, Party B shall be responsible for
            restitution according to the assessment and standards of the
            property management. If, at the end of the lease and the return of
            the premise has been completed, Party B has not paid in full the
            expenses for which it is responsible, Party A may apply the deposit
            toward Party

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            B's outstanding expenses and then return the remaining deposit
            amount without interest to Party B within ten days. In the case of
            late return of the balance of the deposit, after Party B has
            provided the written payment invoice and payment has not been made
            within five days, Party A shall pay the amount of two times of the
            deposit plus interest at the rate of the People's Bank of China's
            one year note for the number of days overdue.

      14.   During the term of the lease, expenses related to water,
            electricity, communications, equipment, security, cleaning and
            property management expenses shall be according to the rules of
            Wenxin Property Management.

            Section VII. Requirements in Using the Premise and the Obligations
            to Repair

      15.   Party B must adhere to the fire safety of the building and district
            in which the premise is located, the regulations and systems of the
            property management, and the laws and regulations of the country.
            Also, Party B is responsible for paying the relevant government
            fees. Party B shall be responsible for cleaning and security.

      16.   Party B cannot damage the structural foundation of the premise and
            shall protect the interior decorations.

      17.   During the term of the lease, Party B shall properly use and protect
            such premise and its equipment and facilities according to the terms
            of use in the Contract. In the case of damage by a person, Party B
            shall be responsible for repair or restitution. If Party B faces
            water leakage in the premise, Party A gives Party B the authority to
            immediately notify the property management company to begin the
            repair. If Party A needs to bear the expenses for the repair, Party
            A must first be informed and the Parties shall together notify the
            property management company to begin the repair.

      18.   During the term of the lease, Party B shall properly use and protect
            such premise and its auxiliary facilities. Party B shall not use
            high voltage electrical equipment to prevent the occurrence of
            circuit damage and malfunction. In the event that accidents caused
            by unsafe conditions result in damage to or destruction of the
            premise and its auxiliary facilities, Party B is solely responsible
            for the loss and cost for the repair. If Party B refuses to repair,
            Party A may repair on Party B's behalf, with all expenses born by
            Party B.

      19.   During the term of the lease, Party B warrants to keep such premise
            and its auxiliary facilities under useable and safe conditions.
            Party B shall regularly examine and conduct maintenance on the
            premise. Party B shall notify and cooperate with the property
            management on such examination and maintenance.

      20.   Party A agrees to allow Party B to additionally decorate. Party B
            shall proceed after it has obtained Party A's written consent on the
            decoration proposal, property management's approval of the fire
            safety, and, in the event that approval from a relevant authority is
            required, the approval from such authority. Of the decorations added
            by Party B and the auxiliary facilities and equipment owned by Party
            A, ownership will be determined based on terms of a written
            agreement.

      21.   If Party B decorates the premise or adds auxiliary facilities
            without the written consent of Party A or in addition to the scope
            consented by Party A, Party A may demand Party B to restore the
            premise to its original condition.

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            Section VIII. Sub-lease, Assignment and Exchange

      22.   During the term of the lease, Party B may sub-lease any part or all
            of this premise to other parties only with the prior written consent
            of Party A. However, the same room for residence shall not be
            divided into portions for sub-lease.

      23.   During the term of the lease, Party B shall obtain the prior written
            consent of Party A if Party B is to assign the lease of such premise
            to another party or exchange such premise with another premise
            leased by another party. After such assignment or exchange, the
            assignee of the lease obligations or the other party of the exchange
            shall enter into an amendment contract to change the party to this
            Contract and continue to perform this Contract.

            Section IX. Conditions of Termination of this Contract

      24.   During the effective period of this Contract, neither Party A nor B
            can withdraw from this Contract nor fail to perform a portion or all
            of the terms of this Contract. If so, the breaching Party shall pay
            a penalty for losses incurred. The Party who seeks early termination
            of this Contract must notify the other Party at least two months in
            advance and the Parties shall enter into negotiations. If the
            negotiations are not successful, the Party who seeks early
            termination shall pay to the other Party the amount of one month
            rent (excluding property management expenses) to terminate this
            Contract. If Party A seeks to sell the premise, Party A shall ask
            the buying party if it will first accept the terms of this Contract.
            Under the same terms of this Contract, Party B has the right of
            first refusal to continue the lease of the premise. If Party A seeks
            to divide the premise into portions, Party B must comply with Party
            A's request; however, Party A shall provide Party B with internal
            corridors. Party A shall deliver a layout of the divided premise
            within two weeks of the signing of the Contract (according to the
            final approval) and included as an Annex to the Contract. In the
            case that the partitioning work to divide the premise is delayed or
            is different from the final proposal delivered by Party A, the
            additional decoration expenses incurred by Party B shall be born by
            Party A. The partitioning work shall be performed on non-working
            days to lessen the effect on Party B's operations. If Party A's
            partitioning work affects Party B's operations, depending on the
            degree of effect, the Parties shall conduct friendly negotiations
            with Party A providing Party B economic compensation

      25.   Party A and B have agreed that, due to force majeure or upon the
            occurrence of any of the following events, this Contract shall be
            terminated and none of the Parties shall be held liable to the
            other:

            (1)   such premise and the land use right covered by such premise
                  shall have been expropriated for public interest;

            (2)   such premise shall have been included in the building
                  demolition permitted by law due to the requirements of urban
                  construction;

            (3)   such premise shall have been destroyed, disappeared or shall
                  have been verified as a dangerous building;

      26.   Party A and B have agreed that, upon the occurrence of any of the
            following events, this Contract shall be terminated. The balance of
            rent already paid by Party B shall act as a breach penalty. If the
            balance of rent is not sufficient to set off Party A's losses,
            compensation shall be made in the amount of the difference between
            the losses thus incurred and the amount of the balance of the rent.

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            (1)   Party B shall have altered the usage of the premise without
                  the written consent of Party A, which shall have caused
                  damages to the premise;

            (2)   Damages to the main structure of the premise due to Party B's
                  fault;

            (3)   Party B shall have, without permission, sub-leased such
                  premise, assigned the lease of the premise or exchanged each
                  other's leased premises with another party;

            Section X. Miscellaneous

      27.   Party A warrants the ownership of the premise is clear. If issues
            arise regarding property right or creditor right and debt, Party A
            shall be responsible for the legal complaints and will compensate
            Party B for its losses.

      28.   Issues not covered in this Contract may be agreed by the Parties in
            supplementary provisions. The supplementary provisions and the
            annexes of this Contract constitute an integral part of this
            Contract. The supplementary provisions and annexes shall have the
            same force and effect as this Contract.

      29.   Party A and Party B fully understand their respective rights,
            obligations and responsibilities at the time of execution of this
            Contract, and are willing to perform this Contract in strict
            accordance with its provisions. In case of breach of this Contract
            by either Party, the other Party shall have the right to claim
            compensation from the breaching Party.

      30.   Disputes arising in the course of performance of this Contract by
            the Parties shall be settled through consultation, failing which,
            the Parties shall submit to the people's court of the local area for
            litigation according to law.

      31.   There are four counterparts of this Contract. Party A and Party B
            shall each hold two counterparts, all of which shall have the same
            force.

Lessor (Party A)               Lessee (Party B)

Zhang Ling                     Shanghai Qianjin Culture Communication Co., Ltd.


Legal Representative:          Legal Representative:

/s/ Zhang Ling

                               Date:

                               Guarantor (Party C)

                               Qianjin Network Information Technology
                               (Shanghai) Co., Ltd.

                               Legal Representative:

                                       6
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                        WARRANTY (HU ZI NO. 0311) ANNEX 1

                                    WARRANTY

      The office premise located at the eighth floor, 755 Weihai Rd, Wenxin
Newspaper Plaza, Jing'an District, Shanghai (hereinafter referred to as the
"Office Premise"), with floorage of 2926.96 square meters, is owned by our
company; however, on December 27, 2004, our company entered into a contract with
Zhang Ling regarding the Office Premise. The contract prescribes that starting
January 1, 2005, the title and use of such Office Premise (including the right
to lease and receive rent) belongs to Zhang Ling under the terms of the
contract. According to the contract, after Zhang Ling has paid the remaining
balance of the housing payment, the property right will be entirely owned by
Zhang Ling.

      If for whatever reason the exchange between our company and Zhang Ling
ceases to be effective, our company guarantees that the three-party leasing
contract entered into among Shanghai Qianjin Culture Communication Co., Ltd.,
Qianjin Network Technology Co., Ltd. and Zhang Ling shall be continued by
Shanghai Sui Feng Real Estate Development Company with Shanghai Qianjin Culture
Communication Co., Ltd., Qianjin Network Technology Co., Ltd. The liability and
rights among the three parties shall be unchanged.

                               Shanghai Sui Feng Real Estate Management Company

                               March 11, 2005

                                       7
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                BUILDING LEASE CONTRACT (HU ZI NO. 0311) ANNEX 2

                          [Layout of building premise]

Signature of both parties at beginning of lease transfer:            Time:

Signature of both parties at end of lease transfer:                  Time:

                                       8
<PAGE>

                BUILDING LEASE CONTRACT (HU ZI NO. 0311) ANNEX 3

Conditions of existing decoration, auxiliary facilities,
and equipment                                                       Total 1 page

<TABLE>
<CAPTION>
                                 Condition at beginning   Condition at
       Type            Number          of lease           end of lease    Comment
------------------    ---------  ----------------------   -------------   --------
<S>                   <C>        <C>                      <C>             <C>
Electricity meter                        Good

Water meter                              Good

Gas meter                                 /

Telephone                           Lines connected

Air conditioning                         Good

Broadband                         One set of optical
                                     fiber cable

                                         Good

Lighting                              Complete

Cable TV
</TABLE>

Condition of decoration:  Simple decoration

Signature of both parties at beginning of lease transfer:             Time:

Signature of both parties at end of lease transfer:                   Time:

                                       9
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                BUILDING LEASE CONTRACT (HU ZI NO. 0311) ANNEX 4

Meter readings of water, electricity and gas use                Total 1 page

<TABLE>
<CAPTION>
       Type           Meter reading at start    Meter reading at end   Comment?
------------------    ----------------------    --------------------   ---------
<S>                   <C>                       <C>                    <C>
Electricity meter

Water meter

Gas meter
</TABLE>

Attachment:  Copy of last payment receipt for water, electricity and gas

Signature of both parties at beginning of lease transfer:              Time:

Signature of both parties at end of lease transfer:                    Time: