Are you loading data from a file from a table ?
Good way to load table is to use the DB2 load utility, rather than INSERT statements.
Do all your validation from the file itself & then writing out the valid data to another dataset in the in the format required for loading (Do a sample download from the table & get the SYSPUNCH to know the format). You may use SORT OURTEC.
Next you use the load utility followed by a table repair (it will be in copy pending).
If you really need to do a lot of INSERT/UPDATE/DELETE to the tables, a common reason for failure is LOCK overflow; in most cases lock size is ROW.
You may need to change the lock size to ANY, do all your maintenace, and then put back the lock size to ROW.
Other reasons for bulk inserts can be the extents of the physical VSAM files reaching 255. Need to reallocate with bigger allocation / purge records from the table
Hope that helps,