I just tried it. Created a new profile, went in and tried to load Fast Dial, and when I restart Firefox to complete the installation of the add-on, once Firefox opens back up, Fast Dial isn't shown on my add-on list and definitely isn't installed. That is both on my default profile and on the profile I just created to test your suggestion.

I'm hoping I get this Fast Dial back because I use it every single day, both for personal use and work use when online since it enables me to keep all of the sites that I visit regularly and even semi-regularly right there on the page, and instead of having to open a new tab, go pick out the site in a bookmark folder, open another new tab, and repeat, I can just simply click on any sites I need and let them open automatically on their own in a background tab. It definitely makes it much easier for me throughout the day.

I am using Firefox 3.5.2 and was using Fast Dial 2.23b1.

I went through everything you suggested. I checked and made sure xpinstall.enabled was set to true. I checked on the Javascript, everything was good. That second link you gave me, to mozillazine, I read through it and found something I hadn't tried, starting Firefox up in Safe Mode. I disabled all add-ons and reset Firefox preferences to default, and tried to install then, and it worked! I now have Fast Dial back and it's working perfectly! All of my bookmarks in Fast Dial are exactly where they were and where they should be.

The only thing I can think of, due to it being successful in safe mode, was that one of my other add-ons was interfering with it and keeping it from being able to install. But, at least now, if I end up with this problem again in the future, I now know exactly what to do to fix it. And hopefully, anyone else who may experience the problem I was having, hopefully this thread will help them.

If this problem should come up again in the future, I'll do a little more testing to see if I can whittle down the problem to exactly what the cause was, instead of just assuming that it was another add-on causing issues. But thanks for all the help and I am so happy to have Fast Dial back and working! This is my most favorite add-on on all of Firefox, and I almost didn't know what to do since I didn't have it for the past few days and couldn't remember all of the sites I had on it. Thanks again!