Wierd error [RESOLVED]

[Mooncatt]

hi i just recently installed the patch. ever since then i have encountered worse bugs than before. the main one thats screwed everything up is that upon firing a torpedo nothing comes out of the tubes! there is no torp in the water at all, no wakes, no torpedo postion on the attack map (modelled in sh3 not sure about sh4) i have tested this numerous times and its like a topedo never got fired at all.
any way i decided to reinstall sh4 altogether. i deleted every folder i could find that was linked to sh4. i also made sure the reg key was gone. half way through install i get this message.......

CRC error the C:/program files/ubisoft/sh4.exe doesnt match the file in the setups.cab file the medium from which you are running the setup may be corrupted please contact your software vender.

what on gods green earth does this mean and how can i fix it.
thanx in advance guys i know your response will be fast as always