I may have found a possible solution to the problem. Look at
this link. It describes that the file which stores cookies information can get corrupted. They suggest deleting the file and everything should go back to normal. Read through and follow the instructions. There is a link that shows how to find this file in your computer.
Here is a more complete explanation: it seems that, for some reason, the file that stores the cookies information, cookies.sqlite or cookies.txt (depending on the version of Firefox), may become corrupt, and then it messes up how and if the cookies are stored. So, if you remove this file from your computer, Firefox recreates it correctly and fixes the problem. The information on how to find this file is at the following page (depends on the operating system you are using):
http://kb.mozillazine.org/Profile_folder_-_Firefox Oh, if you remove the file, you have to go back to the Firefox options and make sure that either the cookies are never removed (keep until they expire) or that you have them included in your "Exceptions..." list. I don't know if removing the cookies file removes the "Exceptions..." information.
<crossing fingers for you guys...>
Let me know if you need more help.
malu
