Well I've had my more than fair share of problems with this game, so to give a bit back, here are a few of the problems, and what I did to fix them.
Data4.Cab file corrupt on install CD.
It is now clear that this problem is due to either not owning a dual layer dvd drive with up to date drivers, or a bad batch of disks. The bad disks are proven by the fact that they would not install on a lot of different drives, and you could not copy the broken file to the hard drive and install from there. The solution is to either find a good disk maybe checking batch numbering. Or get the file in question from another source (which I don't condone but have had to do in this case).
NV4 Disp error Message:
I managed to fix this error on my Nvidia 8600 SLI setup by turning Triple Buffering ON using the nvidia control panel.
Cannot enter Jerusalem:
This maybe due to the data4.cab that I managed to download being one of the "ahem" dodgy ones, I cannot say for sure unless I actually get hold of a bonefide good copy of that particlular file. However, waiting for the patch to be released is the only solution at this point.
I do hope this helps at least some of you out there.