Hi Muru,
The first step to take here is to check the delivery creation process to identify which element is causing the error in the incompletion process.
Can you see the same error when creating the IBD in VL31N? To catch it in debugging of the SPED output you can set parameter ledsp_debug_mode to 'vl10'. In debugging you can check the entry of XVBUV table to see what is incomplete.
Regards
Stephen