Did you trace him? (or a test case in dev?) - can you provide output of STAUTHTRACE?
Any other general problems could be:
* Is P_PERNR activated in T77S0 / lookup with tcode OOAC?
* Is the object activated for tcode in SU24?
* Is the IT0105.0001 connection between SAP user and pers.no. valid in the current time frame?
But a trace will give a lot of feedback on the real issue. The setting with P_PERNR 0316 / PSIGN = E should be sufficient IMHO.