Currently I am upgrading a large school network from Netware to Windows Server 2003. Part of the migration included moving AccPac over to the new system.
Whilst most of this process went extremely smoothly I had a problem whereby when logged in as a normal user (with limited rights onto the local PC) couldn't use AccPac properly. AccPac would load absolutely perfectly but when the user selected an icon within the program (e.g. "Reconcile Bank Statements"). An error occured with the message :
"Control Not Properly Installed"
The answer to this problem was to go into the AccPac runtime directory (on the server) and run a utility (as an administrator) called regacc.exe on each workstation. This tool runs through the registry and reregisters all the .ocx / .dll files necessary so that regular users can access them.
This fixed the problem for me. I have noticed a lot of people with the same problem whilst looking for a solution on Google, so hopefully this helps you also.