Let me add a bit more. There are many sources to get extensions. The 'official' one is Mozilla Update (
https://update.mozilla.org/). Any extensions on this site have been proofed for compatibility by official people. However, it takes a while for extensions to be listed there, and for updates to be listed.
Two alternates: Extensions - MozillaZine Forums (
http://forums.mozillazine.org/viewforum.php?f=19) and The Extensions Mirror Forums (
http://www.extensionsmirror.nl/index.php?act=idx). The MozForum site has discussions regarding new extensions, often with the extension developers discussing the bugs with users. The Mirror site also has unofficial "patched" updates for extensions that the original authors haven't upgraded to work with the current version of Firefox.
You mentioned NukeIt, by which I believe you meant Nuke Anything. You can get a patched version here: Nuke Anything 0.2 - The Extensions Mirror (
http://www.extensionsmirror.nl/index.php?showtopic=77).
I hope you were not offended by my SpellBound suggestion. I use it all the time. I had about 5 misspellings in this post alone.