1. Click on the Firefox menu (the orange button in the top left)
2. Click Options on the right hand side of the menu
3. Click on the Advanced section (the cog icon) on the right hand side of the dialogue box.
4. In the dialogue box, you will see some tabs that read general, network, update and encryption. Click on Update.
5. Un-check the first three boxes and press Okay.
6. Done.

Your are using Firefox 6.0 and version 6.0.1 is a security update about a fraudulent certificate. It won't make your extensions incompatible.

If you want to keep the control on Firefox updates, check Ask me what I want to do in the Update tab of the Advanced Options panel. See Options window - Advanced panel - Update tab.

Not working. Still seeing the pop out window for firefox updater. I need to click yes or no to continue. I think this might be windows security options...:( i'll try to play around a bit and see...