I don’t see how this can be related to uBO. If your Firefox crashes, you should submit the crashes to Mozilla, that is definitely not normal.
Well, since this only occurs when uBO is active (and no other add-on) I thought that this would be related to uBO. I have sent all the crash reports to Mozilla anyway , via the automated crash report window that appears after a crash. Maybe there is a better place to report this issue to Mozilla?
Tanks.