Hello everyone,
I've faced the same issue while trying to evaluate sample in inspection lot. I've find out the the Q5 026 error is returned only when not all of sample inspection characteristics are evaluated.
For example, inspection operation has 4 characteristics and only 2 of them are evaluated. In this case if you will try to evaluate sample BAPI_INSPOPER_RECORDRESULTS will return E Q5 026 error. And if all of characteristics will be evaluated then BAPI will work fine.
This approach has solved my issue with Q5 026 error. Hope this would help someone.
Cheers!
Vitaliy