Found a solution to https prob
I had that problem too, but I've found a solution that works for me.
1. Download Firefox from Mozilla's Site - firefox-188.8.131.52.tar.gz (8.1MB) and unpackage it in somwhere in ~ preferably. The package should be binary, and not source so no compiling. (ie mine was the binary) The folder will be called "firefox", rename it to "firefox-184.108.40.206".
2. Goto /usr/lib and rename the firefox-220.127.116.11 to firefox-1.5.0.x.
3. Copy the ~/firefox-18.104.22.168 to /usr/lib.
4. Run firefox normally, and check if it acesses Gmail or Firefox Extensions without the error.
5. If all works, Horray. I deleted the firefox-1.5.0.x from /usr/lib as it is no longer used.
I hope that helps.