Upgrade from 7015 problem

We are using build 6.0.0.2 in production environment.
In a test environment I upgraded the manage engine servicedesk build from 6.0.0.2 to 7.0.0.15 from a series of steps successfully. An error occured when i try to upgrade from build 7.0.0.15 to 7.0.0.16 or 17 or 20 . Why did it occured? Any help wellcome. Logs are attached.

* Version of the product: ServiceDesk Plus 6.002 (7.0.015 test)
* Service Pack Version: SP2
* Operating System: Windows 2003 SP1.
* JDK/JRE Version: built in servicedesk jre 1.5
* Browser and Version: IE 6.0
* Details of the problem:
o UpdateManager.bat problem
o The relevant log files are attached
* Thread Dumps are attached
* CLASSPATH environment variable : n/a
* Database Server : DOSYACI\SDP
o SQL Server 2000 SP4 (8.00.2039)
o Collation Name: Turkis_CI_AS changed to SQL_Latin1_General_CP1_CI_AS
o Owner: sa

Thanks in advance...