Okay this is actually a tip by Azmodie (aka special K),
When i upgraded to firefox 3 i noticed most of my add-on's didn't work. He suggested i download the nightly build tool kit, which has a compatibility tool for add-on's. Install that, and then load each individual add-on that wasn't compatible one by one.
Worked fine, and now my fav add-on's are back
Well done azmodie
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