No, it would be a bad idea to rename the apwin directory to Payables.

For us to be able to provide further assistance, we need to know the name of the file you are using to perform the upgrade install. One way to determine if you are using the correct install is whether you are prompted for an install code and serial number - a service pack does not ask for this but an upgrade does.

If it is APSPP20150609.EXE and around 36Mb in size, then this is a service pack file and not the appropriate upgrade installer program for you. To install version 9.2A, you need to download AP5P20150609.EXE from the Upgrades link, which is about 88Mb in size.