Re: How to set Approver in PTARQ t-code.

First check in t-code PO13 the reporting relation ship 002 is maintained from employee position to his manager position. And check that manager position is holding with manager employee code or not.

And also check the BADI PT_GEN_REQ method FIND_RESP_AND_DEFAULT_NEXT_PRC is implemented to determine approver in your system if any customization in your case.