I had FS update patch 9.1 installed but then i accidently deleted some files out of my FS2004 folder, (bit of a long story really) well it all seems to be ok anyway, i thought i would reinstall 9.1 to make sure it was still there but it won't let me install it because it says i have it, but i deleted the uninstall icon so i can't uninstall 9.1 so i can reinstall it.
I have traffic 2005 and when i open up the check taxi speed box it says i have 9.0. but i can't install 9.1. I know its a bit complicated but all i want is the uninstall file. and i'm not going to remove the whole of fs2004 because i've got to much add-ons and it will be a nightmare.
I hope this helps, you may have gone too far.
This is what MS has to say about uninstalling 9.1.