Thunderbird 2.0.23 and Win 7 question

I have two copies of Thunderbird 2.0.23 (build 20090812). I notice that the dates on the exe's are different, but when I do an about I get the same build number.

Here is the problem I am having....I am sure that it is a Windows 7 "feature" but I can't figure out why it is happening...

I have two different thunderbirdportables installed that go to two different mail accounts (I know that I can combine them....I don't want to). In Windows 7 one of these exe's is flagged as requiring an elevated permissions to run...so I have to see the prompt of do I want to run the exe....while the other account has no problem and runs in the regular permissions.

I have read up on Win 7 and tried to figure out what could be causing the thunderbird exe to be flagged as needing to run as Admin....and I have found what windows saysing....which is that it runs a process to examine the exe to determine if windows thinks it needs elevated permissions....and that some of the things that can cause this are the exe being named setup.exe and other things....none of these are a problem for thunderbird.

Does anyone have an idea of why windows is doing this?