<PAGE>

                                                                  EXHIBIT 10.8.1

                                PAYMENT GUARANTY

         This Payment Guaranty (this "GUARANTY") is made as of April 25, 2006,
by CONCORDIA HOMES OF NEVADA, INC., a Nevada corporation, ("GUARANTOR") in favor
of ASI Technology Corporation, (collectively, "LENDER").

                                 R E C I T A L S

         A. Guarantor is executing this Guaranty to induce Lender to extend a
loan (the "LOAN") to Aviano, LLC, a Nevada limited liability company
("BORROWER") in the principal amount of Eight Hundred Thousand and 00/100th
Dollars ($800,000.00).

         B. The Loan is evidenced by a promissory note (the "NOTE") made payable
to Lender in the principal amount of the Loan. The Note will be secured by a
Deed of Trust With Assignment of Rents (the "DEED OF TRUST") covering certain
real and personal property, as therein described (all collectively, the
"PROPERTY"). The Note may also be secured by other collateral.

                                    GUARANTY

         1. GUARANTY OF LOAN. Guarantor unconditionally guaranties to Lender the
full payment of the Loan, and unconditionally agrees to pay Lender the full
amount of the Loan. This is a guaranty of payment, not of collection. If
Borrower defaults in the payment when due of the Loan or any part of it,
Guarantor shall in lawful money of the United States pay to Lender or order, on
demand, all sums due and owing on the Loan, including all interest, charges,
fees and other sums, costs and expenses.

         2. LOAN. In this Guaranty, the term "Loan" is broadly defined to mean
and include all primary, secondary, direct, indirect, fixed and contingent
obligations of Borrower to pay principal, interest, costs and expenses which may
be owing at any time under the Note or the other Loan Documents, as any or all
of them may from time to time be modified, amended, extended or renewed.

         3. RIGHTS OF LENDER. Guarantor authorizes Lender to perform any or all
of the following acts at any time in its sole discretion, all without notice to
Guarantor and without affecting Guarantor's obligations under the Guaranty:

                  (a) Lender may alter any terms of the Loan or any part of it,
including renewing, compromising, extending or accelerating, or otherwise
changing the time for payment of, or increasing or decreasing the rate of
interest on, the Loan or any part of it.

                  (b) Lender may apply any payments or recoveries from Borrower,
Guarantor or any other source, and any proceeds of any security, to Borrower's
obligations under the Loan Documents in such manner, order and priority as
Lender may elect.

                  (c) Lender may release Borrower of its liability for the Loan
or any part of it.

<PAGE>

                  (d) Lender may substitute, add or release any one or more
guarantors or endorsers.

                  (e) In addition to the Loan, Lender may extend other credit to
Borrower, and may take and hold security for the credit so extended, all without
affecting Guarantor's liability under this Guaranty.

         4. GUARANTY TO BE ABSOLUTE. Guarantor expressly agrees that until the
Loan is paid and performed in full and each and every term, covenant and
condition of this Guaranty is fully performed, Guarantor shall not be released
by or because of:

                  (a) Any act or event which might otherwise discharge, reduce,
limit or modify Guarantor's obligations under this Guaranty;

                  (b) Any waiver, extension, modification, forbearance, delay or
other act or omission of Lender, or its failure to proceed promptly or otherwise
as against Borrower, Guarantor or any security;

                  (c) Any action, omission or circumstance which might increase
the likelihood that Guarantor may be called upon to perform under this Guaranty
or which might affect the rights or remedies of Guarantor as against Borrower;
or

                  (d) Any dealings occurring at any time between Borrower and
Lender, whether relating to the Loan or otherwise.

                  Guarantor hereby expressly waives and surrenders any defense
to its liability under this Guaranty based upon any of the foregoing acts,
omissions, agreements, waivers or matters. It is the purpose and intent of this
Guaranty that the obligations of Guarantor under it shall be absolute and
unconditional under any and all circumstances.

         5. AUTHORIZATION; NO VIOLATION. Guarantor is authorized to execute,
deliver and perform under this Guaranty, which is a valid and binding obligation
of Guarantor. No provision or obligation of Guarantor contained in this Guaranty
violates any applicable law, regulation or ordinance, or any order or ruling of
any court or governmental agency. No such provision or obligation conflicts
with, or constitutes a breach or default under, any agreement to which Guarantor
is a party.

         6. GOVERNING LAW. This Guaranty shall be governed by, and construed in
accordance with, the laws of the State of Nevada.

         7. COSTS AND EXPENSES. If any lawsuit or arbitration is commenced which
arises out of, or which relates to this Guaranty, the Loan Documents or the
Loan, the prevailing party shall be entitled to recover from each other party
such sums as the court or arbitrator may adjudge to be reasonable attorneys'
fees in the action or proceeding, in addition to costs and expenses otherwise
allowed by law. In all other situations, including any Insolvency Proceeding,
Guarantor agrees to pay all of Lender's costs and expenses, including attorneys'
fees which may be incurred in any effort to collect or enforce the Loan or any
part of it or any term of this Guaranty.

                                       2
<PAGE>

         8. CONSIDERATION. Guarantor acknowledges that it expects to benefit
from Lender's extension of the Loan to Borrower because of its relationship to
Borrower, and that it is executing this Guaranty in consideration of that
anticipated benefit. Guarantor represents and warrants to Lender that such
consideration constitutes the receipt by it of full, adequate and sufficient
consideration for the incurrence by each such Guarantor of its respective
obligations hereunder.

                                        GUARANTOR:


                                        CONCORDIA HOMES OF NEVADA, INC.,
                                        a Nevada corporation


                                        By:  /S/ GIDGET GRAHAM
                                             -----------------------------
                                               Gidget Graham, President


                                        Address Where Notices to
                                        Guarantor are to be Sent:

                                        Concordia Homes of Nevada, Inc.
                                        980 American Pacific Drive
                                        Suite 100
                                        Henderson, NV  89014


                                        Address Where Notices to
                                        Lender are to be Sent:
                                        ASI Technology Corporation
                                        980 American Pacific Drive
                                        Suite 111
                                        Henderson, NV  89014

                                       3