Hi Ranadheer
Are you getting this error in OBBH or GGB1? I have not personally seen this error message, but, Class 8 is meant for Document header level substitutions and class 9 is meant for Document line item level substitutions.
If you need to use fields from both BKPF and BSEG tables, please use substitution at complete document level.
Yes, we can have multiple substitutions for a single company code with the same call point. In fact, you can define multiple substitution with the same call up point say XXXX and this can be assigned to as many company codes as possible.
Regards
Sowmya