RCT3 Crashes Need Help

I recently bought RCT3 and Soaked! I installed them, patched Soaked with patch #1 then cracked the game. (To run it without the CD) I played it for hours last night, then I tried to play it this morning, and it went past the intro and crashed. So I entered the game like five more times. On the fifth try it went into the game and I played the missions for Soaked, after about 5 mins into the mission it crashed to desktop. So I re-entered the game. Again crashing after intro. Then after a few tries it entered the game, and same thing again, play for 5 mins and crash. I went into the game folder and looked at the 'crashdump' file or whatever and the first few lines were this:
Unhandled exception "access violation" in "C:\Windows\System32\ntdll.dll" at 001b:77f755e9 Read from location 01b33c6c cuased an access violation
So I downloaded ntdll.dll and replaced my old ntdll.dll with the new one, but I still have the problem. Any ideas? thanks.

Specs:
MSI Nvdidia NX 6600 GT
1 Gig ram
Windows XP
AMD Athlon 2000+