Hi Arun Singh,
It is an application error.
Please refer SAP notes:
1845200 - Upgrade fail when table contains too many UDF
Symptom
When you upgrade from 8.82 PL10 to 8.82 PL11, if there are too many UDF in
table 'ADOC', upgrade will fail.
Cause
Application error.
Solution
SAP intends to provide a patch or patches in order to solve the problem
described.
The section Reference to Related Notes below will
list the specific patches once they become available.
The
corresponding Info file of the patches in SAP Service
Marketplace will also show the SAP Note number.
Be aware that these
references can only be set at patch release date.
SAP will deliver patches
only for selected releases at its own discretion, based on the business impact
and the complexity of the implementation.
Thanks & Regards,
Nagarajan