Hi
Which Doc Type you use to settle RA postings into FI? Locate that Doc Type from the RA Configuration
Check what No. Range Object is assigned to it in OBA7. Check the number range assigned in FBN1
It seems your no. ranges are reset in this client. Did anyone transport the number ranges?
Check FB03 what the last document number was for this Doc type and accordingly adjust the number range in FBN1
Ajay M