First, please update to Firefox 17.0.1 [[Update Firefox to the latest version]] Then, do you want to delete a bookmark, or export it to a different browser? They are two different things.

See: *https://support.mozilla.org/kb/how-do-i-use-bookmarks *https://support.mozilla.org/kb/Deleting+Bookmarks If bookmarks and/or history working properly then you can check for problems with a possibly corrupted places.sqlite database file in the Firefox Profile Folder. *http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox *https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file