756 SEQUENTIAL BUFFER SCAN FAILURE

Explanation
 The database might be corrupted. 

User response
 Check database integrity. If the problem persists,
contact the installation DBA.
If the cause
is an IMS Index Builder internal
error, a snap dump is generated in the IIUDUMP data set. This snap
dump is required for analysis.
The general-purpose
registers at taking the snap dump contain the following information:

R2

RBA of the database block or CI

R3 

Storage address of the database block or CI 

R4 

Storage address of the segment currently processed