OK, nothing works it seems - only reliable workaround is choosing 'Save As' in entourage, choosing to save it as simple text, then opening that saved document in textedit and copying from their (as opposed to copying in to textedit and copying out again)
I suppose the fixes I referenced earlier must be out of date though as the preferences files have either completely changed or just been renamed - i deleted the maxprog/preferences and the com.maxprog plist in place.
Fix this issue for us and we'll be buying another three copies at least, but the reliability is key to us!
This worked fine until yesterday and there have been no changes to the computer - a new iMac running 10.5.6 (since upgraded to 10.5.7 to no avail - was running 6.3 when it started crashing, having upgraded to 6.5 the problem continues.)