I've encountered the following problem on a system running Firefox on Windows XP: when you try to run a podcast, the following error message comes up:
QuickTime failed to initialize. Error # 0
Please make sure QuickTime is properly installed on this computer.
That's in one dialog box. After clicking OK, another dialog box comes up, with the message
The plug-in performed an illegal operation. You are strongly advised to restart Firefox.
This started happening after the latest update to FireFox was installed. I tried reinstalling Firefox and the plugin. Same result.