Linux Mint Forums

Please check the Ubuntu forums since upgrading the Ubuntu repos to 7.04 is not recommended or supported action in mint.

you have a few options:

using synaptic you can reinstall firefox.
or
using synaptic you can remove firefox and then install firefox.
or
look/wait for an update to firefox to be released.

I haven't seen any recent posts about firefox errors on 7.04 fiesty.

it maybe gremlins and a reboot later it all works.

The extreme fix is to reinstall mint and not hit the upgrade to 7.04 button but just update packages.

good luck

install swiftfox... as far as I heard it had no lockups that firefox is experiencing in edgy

you can install it easily via automatix (http://www.getautomatix.com)