I'm unclear which version of Windows 7 is "Full retail".
I have Flex Builder 3 and Flash Builder 4 running on Windows 7 Ultimate 64 bit without any issues.
After my upgrade I did have to 'clean' a few work spaces using the '-clean' flag. I doubt you'd have that issue if you did an install from scratch.
sorrry, I just mean the standard Windows 7 HOME version that comes with new laptops being sold.
Funny thing is, I just rang Adobe and they said Flex Builder 3.01 will not run under Windows 7.
So I guess that Adobe person was incorrect or just being overly cautious ?
There is still a Home Basic and Home Premium. But, I've tested against neither. I'd be surprised if they didn't work.
I suspect the person you spoke to was reading the system requirements for Flex Builder, and since FB3 was released before Windows 7 it is probably not a supported platform.