MacQFE will only run on Powermacs running OS7.1 or later (OS versions before 7.5.3 will require Drag and Drop to be installed), it also requires Applescript for some functions.
If MacQFE crashes your Mac then try all the usual remedies (Disk First Aid, rebuilding the Desktop) before contacting the author. If the crash can be consistently reproduced then please give the author as much information as possible about the circumstances under which it crashes, including, if you can, a screen grab (shift-command-3) of any error messages.
The author will make every attempt to provide support for this software, even to unregistered users.
Send bug reports to giles.gqt@otranto.demon.co.uk
This is unlikely to be due to MacQFE, but you can try the following solutions.