I started to get this really annoying error every time I went to page that had a Quicktime .mov embedded in it while using FireFox:
QuickTime failed to initialize. Error #0
Turning to Google (the modern equivalent of asking my dad which would usually evoke a “look in the dictionary/encyclopedia”), I found several helpful tidbits that didn’t help.
One bit of advice called for uninstalling Quicktime, using Microsoft’s Windows Installer Cleanup (which was useless since there were no remnants of Quicktime left to clean), restarting then reinstalling Quicktime. No luck. Same problem.
The next solution was to go to Control Panel–>Quicktime–>Browser Tab–>MIME Types and reset that. No luck. Same problem.
The third solution has too many specific steps to paraphrase:
1. Close Firefox or Mozilla Suite.
2. Delete all “npqtplugin*.dll” files (npqtplugin.dll, npqtplugin2.dll, etc.) from your browser’s installation directory plugins folder.
3. Delete all “npqtplugin*.dll” files from the Quicktime plugins folder (usually C:\Program Files\QuickTime\Plugins).
4. Go to “Start -> Control Panel -> Quicktime -> Browser (tab) -> Mime Settings” and reselect your preferred media types.
If you still have problems, close Firefox or Mozilla Suite, open the “Mozilla” or “Firefox” folder in the profile folder location and delete the file “pluginreg.dat”
Then, while reading through a bunch of search results, I happened to read a summary that mentioned a different problem with Firefox when set in compatibility mode. I suddenly remembered that I changed this setting because of performance issues with Firefox. Righ-click Firefox’s Alias, Go to Compatibility Tab, Uncheck “Run this program in compatibility mode for:” and… Fixed! Phew!