I have this issue in LL and MM in FF 3.6.10 or above, including 4.0 beta 8. I wonder if Xmarks is the root cause of this problem...
Edit...
It seems I was right, now I could export them as HTML files and use them in Konqueror and Rekonq.
Edit...
It seems I was right, now I could export them as HTML files and use them in Konqueror and Rekonq.