Error while executing PRC: Generate Draft Invoices for a Single Project program

Pasting the Log File Generated. Please help me out in this issue. Thanks in advance.

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Projects: Version : 11.5.0

Copyright (c) 1979, 1999, Oracle Corporation. All rights reserved.

PAIGEN_SINGLE module: PRC: Generate Draft Invoices for a Single Project
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Current system time is 04-SEP-2012 12:48:47

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...Setting Sets Of Books...2
...Regeneration of invoices 
...Single project invoice generation 
 Calling AR Install Extension...   

 Calling Get GL-PA Dates and Periods API 

 PA-GL API Return Code  : 

 setting glob vars 

 Calling Delete unapproved/unreleased invoices ...
 Call Convert APIreturn stat...
.... Before execute update. 
.... After execute update. 
Entering paibih() 
PEvent_Num=0,Execute the PLSQL Blk to find Auto Evt is not billed or not 
 
 Leaving paibih() 
return stat...Calling paiadj