Unable to Approve a PO

Hi,

I am facing Problem as follow:-

1) I have create a Position and employee and assign this position to this employee and after that i create Approval Group and then Assign Approval group to Position and assign the Employee to User and then run Fill Employee hierarchy but when i create Requisition and try to approve then status is always incomplete.

Note:- We want to have individual Position and that does not report to any one so no need to change in Position hierarchy for addition of subordinate.

Regards