Force Feedback or the FSPort mission?
Force Feedback originally wasn't working in 3.5.5 but DID work in retail and 1.2 of FS2. It also worked in other games. I changed the center spring strength (turned it down from 150 to 100) and suddenly 3.5.5 and my _t build both started using ForceFeedback, I did explain this in the thread about the new launcher (One with joystick code) and in my Bugzilla bug.
FSPort mission: Honestly..I don't know about in retail. It'd take me a while to run through the missions again to get to the right one to test it in FS:Retail. It didn't work in 3.5.5 though, crashed out even sooner than the _t build. See I get about 1sec of play using the _t build. In 3.5.5 release it never displays anything, just immediately drops out. I do know the same mission is playable with the exact same FSSCP setup (Same _t build, same VPs, etc.) on a friends Machine.
My hardware:
Athlon XP2200+
512 PC2100 DDR (Nobrand)
GeForceFX5600 (256meg, non-ultra)
Hitachi 60Gig drive (I don't remember what model)
I have the output to MSInfo32/DxDiag if anyone wants 'em? I'll post 'em on my website. Might not be up if you've read this with a few minutes of me posting but I'll stick 'em there in a moment.
http://marajin.w-ww.org/afflawnsysinfo.shtml