I've read alot about this topic but the most obvious solution doesn't work.
I have an image of the cd running and i still get the Land data read error when i try to start a mission.
New patch installed from this site.
Hit me with a solution :D

Assuming you're using an image created from your genuine W:A CD, your CD was probably damaged an the image is corrupted.

I have a 2000/2001 THQ whatever release on which mission maps are messed up, starting from the 10th mission or so the maps used were all wrong causing one mission to be unfinishable without cheats (and all worms placed at 0,0) and the one afterwards always crashing the game.
But you should really check if your CD is damaged first ;S