Bookmarks deleted automatically, some bookmarks change their links

I use Ubuntu 10.10 and use Firefox 3.6. I have noticing some weird problems lately with Firefox Bookmarks. Now I keep all my bookmarks in the toolbar. The first time when it happened, the bookmarks started scrolling left-to-right (i.e. the bookmarked icons kept moving) on their own! On top of that, Some of the bookmarks created multiple copies of their own in place of the other icons. So for example, suppose I had bookmarks for yahoo, google, gmail, facebook, twitter etc, All I could see is 4-5 icons of yahoo and 2-3 icons of google and none of the others (just an example). So I reset all my bookmarks again. But after few days the same problem happened!

Any solution?