solution for firefox18 problem Rated 5 out of 5 stars

I have the same problem after update to Firefox18 - but I found a solution without creating a new profile!

1. disable FoxyProxy
2. go to the Firefox network settings and unselect "Auto-detect proxy settings for this network", I've inserted my default proxy settings at "Automatic proxy configuration URL:"
3. enable FoxyProxy

This review is for a previous version of the add-on (4.1.1-signed).