Exhibit 10.255

NINTH LEASE AMENDMENT- PPD Development, LLC

THIS NINTH AMENDMENT of Lease (this “Amendment”) is made and entered into this
31st day of August, 2007, by and between Greenway Office Center L.L.C. (the
“Landlord”) and PPD Developments, LLC. (the “Tenant” ).

RECITALS:

WHEREAS, Tenant, through PPD Development, LLC (Tenant’s predecessor in interest)
and Landlord entered into lease dated April 30, 2001, as amended on August 15,
2001, August 25, 2003, March 22, 2004, May 17, 2004, December 5, 2004, June 30,
2005, July 29, 2005 and March 1, 2006, with respect to certain space located at
8551 Research Way, Middleton, Wisconsin(the lease, as so amended and as amended
by this Amendment is referred to as the “Lease”) in a building known as the
Greenway Research Center (“Building”); and

THEREFORE, for good valuable consideration, the receipt and sufficiency of which
the parties hereby acknowledge, Landlord and Tenant agree as follows:

 

1. Tenant shall have the right to expand Existing Premises by leasing Suite 130
in the Building, which consists of 12,984 Square Footage (the “Suite 130
Expansion”).

 

2. Section 1.10 of the Lease is hereby replaced with the following: “Tenant
shall pay rent according to Lease. Starting September 1, 2007, Tenant shall pay
additional rent for the Suite 130 Expansion space as follows:

 

Period or Months of Term

   Annual Rate Per Square Foot    Monthly Base Rent 8/1/2007 to 2/28/2008    $
12.77    $ 13,817.14 3/1/2008 to 2/28/2009    $ 13.15    $ 14,231.65 8/1/2009 to
2/28/2010    $ 13.55    $ 14,658.60 8/1/2010 to 2/28/2011    $ 13.95    $
15,098.36 8/1/2011 to 2/28/2012    $ 14.37    $ 15,551.31 8/1/2012 to 2/28/2013
   $ 14.80    $ 16,017.85 8/1/2013 to 2/28/2014    $ 15.25    $ 16,498.39
8/1/2014 to 2/28/2015    $ 15.71    $ 16,993.34 8/1/2015 to 11/30/2016    $
16.18    $ 17,503.14

 

3. Landlord shall deliver the space in “as is” condition

 

4. The first sentence of Section 2.4 is hereby replaced with the following:
“Tenant Improvement Allowance: Landlord will provide Tenant with a Tenant
Improvement Allowance equals to Ninety Thousand and 0/100 Dollars ($90,000).”

 

5. Except as specifically amended herein, the Lease is hereby ratified and
affirmed and shall remain in full force and effect. Each party acknowledges that
the other party is not in default under this Lease nor does either party know of
any circumstances that, with the giving of notice, would result in the other
party being in default under this Lease. The Lease, as herein amended, shall
continue in full force and effect.

 

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IN WITNESS WHEREOF, Landlord and Tenant have executed this Amendment as of the
date it is executed by both of the parties.

 

TENANT:     LANDLORD: PPD Developments, LLC.     Greenway Office Center L.L.C.  
  By:   T. Wall Properties Management Corp.,
    Its Property Manager By:   /s/ William J. Sharbaugh     By:   /s/ John Kothe
Name:   William J. Sharbaugh       John Kothe, Vice President of Operations
Title:   Chief Operating Officer       Date:   August 30, 2007     Date:  
August 31, 2007

 

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