Thunderbird 2 and NIS 2011

Currently I'm running Windows 7 Ultimate 32-bit, Avast Free, and Thunderbird v. 2.0.0.24 (the last version of Thunderbird 2).

 

Avast free is giving too many false positives lately and I'm tired of chasing them down.  It's new v.6 is still buggy.

 

I'm thinking of installing NIS 2011.  I'm worried about how well it plays with Thunderbird 2.  I've been reading some horror stories about Thunderbird 2 and NIS 2010, so naturally I'm worried about NIS 2011

 

I don't want to go to Thunderbird 3 for various reasons. 

 

Does NIS 2011 work well with Thunderbird version 2?  Any thoughts?

 

Thank you very much!