I'm also having a similar issue. I recently bought The Witcher 2 and I keep having crash issues so I looked up some stuff on how to fix it and the most common answer is to update my drivers. I have a Nvidia GeForce 8600 GTS video drive 32-bit for vista. I've tried downloading the new update for it but then when i go to the file location and try to open it it says "Please enter the folder where you want to save the Nvidia driver files. If the folder does not exist, it will be created for you." and when I try to accept the generated folder I get the non 7-zip archive error. I've been trying to fix this for a couple hours and I'm starting to get frustrated. While looking this problem up it brought me here so I was hoping someone could help.
I found that my Anti-Virus program (Vipre Internet Security 2012) was preventing me from installing or uninstalling Thunderbird. I had enabled their Process Protection system prior to this. I remember that when I first started to delete Thunderbird, I was asked if I wanted to allow this program to make changes to my system. I wasn't sure and had decided to stop the uninstall so I chose no. That is when all the troubles began.
If you have a firewall setup to prevent changes being made to your system, turn it off until you have completed your install. That should allow you to install Thunderbird.