Hey Alex,
If you have enhanced or made any changes on the datasource , make sure you activate the extraction structure first from LBWE, before proceeding any further.
Once activated :
Setup table for this datasource should be : MC11VA0ITMsetup.
So go to se16 n check if it's holding any value or not. If yes, go to LBWG & give application value as 11 & delete it.
After the deletion, go to OLI7BW & fill it.
Re-check in rsa3 or se16-> MC11VA0ITMsetup.
Regards,
Suvro