To add more information to the question, the problem started occuring around the same time as I installed the flash debugger tool (to get flash
bug working in firefox)...
Not sure if the 2 events are related?
Have you uninstalled the debugger tool?
Yes I've uninstalled the debugger, and Fireworks individually, and I've uninstalled the full Adobe CS5 Suite - then re-installed it all and I till have the same problem...
Surely i'm not the only one experiencing this issue...
On another note, a friend (with the same spec work pc) installed the flash debugger and his Fireworks install is fine.
I'm using Windows XP in case you were wondering.
I managed to fix the problem by going to a previous system restore point (1 month ago) then re-installing adobe cs5 suite.
Not sure what the issue was though...