This error, usually occurs when asking help/about to show rev info, and is generally caused by the download.ini file, pointing to incorrect drives, either on local machine, or on network. Common cure, is to delete the "download.ini" file. Start Compass by C:\COMPASS\EXE\DOWNLOAD.EXE, or if on a network N:\COMPASS\EXE\NETLOAD.EXE, (where N is the networks mapped drive) initially, to correct downlaod.ini file. Also see DOC "Network installation procedure".

Error can also be caused by a upgrade patch, installed to its OWN DIRECTORY. To cure this issue, reinstall patch to current Compass Directory.