Bookmarks lost! Errors.

Hey, i have been using portable firefox for a while now and well i noticed it has one big error or fault in it and i'd like it if anyone cares to help me find a solution.

So here goes.

I opened a tab before and never realized what it was and after i did not long after the tab took over all my bookmarks. In other words when you look at bookmarks it says the same thing over and over again and replaces my old bookmarks.

I tried to delete it but it's no use and i tried to refresh firefox and reinstalling it but no use.

Just lately now i find that each time i open firefox all my bookmarks disappear permanently and now i can't get a single one back. I even tried to restore a backup and no use.

What is happening? Can anyone help me out here. Will i have to start from scratch again or something?