I try to start an event in Flatout Ultimate Carnage called stunts and I begin to load it and it freezes and I get the error, ZLib error (-3) incorrect data check! it pisses me off because I just got the game today and I dont know how to fix this. Can anyone give me a fix? Thanks

COME ON! THERE HAS TO BE AN ANSWER!!
HERE ARE MY SYSTEM SPECS:
Nvidia 8600m GT
Intel Core 2 Duo T8100 - 2.1 GHz
500 GB hard drive space
HELP, Please someone find a solution. This problem pisses me off enough and its only on the stunt event in Flatout Ultimate Carnage. No other event has this error.

Actually, Flatout Ultimate Carnage is not on GOG.com, it was released in 2008. The game on GOG.com is the first one, released in 2004.
So if you're referring to the one downloaded from here, the answer to your question is in the other question thread; to solve this you could also download the new installer (it was updated the 22nd of december, I believe)

I tried installing that one, but the files required are not in the installation. Any other solutions?

Just to help us out a bit more: Are you on XP, Vista or Linux/WINE. And is your OS running at 32 or 64bit?
Most problems I can find around this issue (all Flatout games) relate to changes to XP system files, corrupt bfs files or a broken/updated-incompatiable zlib.dll.
Also: Which files are missing for the linked solution? There could be something there as well.

Im on Windows Vista Service Pack 1 - 32 bit
So as I said above, the game minimizes out and gives me the error, ZLib error (-3) incorrect data check.
But Ois, what do you mean by "files missing for the linked solution".
Do you mean which files are in the error?

Okay, I'll try track down the Vista issue.
No, in the post above mine you said
I'm guessing you tried the bfs file unpacker, but could not proceed since certain files did not exist?

Yes. I cannot proceed with the bfs unpacker because the files do not exist. Files like common1 and common2.bfs. Those were for Flatout 2.
BUT, do you think my game could be a defective copy? What would I do since I did not keep the receipt for the store I bought it at?

If you have no (zero) bfs files, I would suggest you reinstall the game. They should be located in the main game dir.
If you have bfs files, but of different names than the ones listed in the solution, use those files instead.
(just caught your ninja edit: bfs file names should be different!)
Check the CD/DVD itself, you may be able to find and copy the bfs files to the HDD.
Unfortunately, if you did not keep the receipt you don't have much options.
Check with the publisher/developer support and see what they can do: Small chance you can send in a defective disc, or scan the box, disc, manual etc... to show legitimate proof of ownership.
I can't promise anything there, most places don't do this any more. So give their support systems a email/call before you proceed.