AP 8.1F and previous versions were installed to \Softrak\APWIN and the program file was APWIN.exe. However AP 9.2A is installed to \Softrak\Payables and the program file is Payables.exe.

GL 9.2 will continue to retrieve and work fully with AP 8.1F (there isn't any 8.3).

It sounds as if you are trying to install the AP 9.2 Service Pack without first having installed the full Payables module. What is the name of the file you are trying to install?