I have 2 pc's. One with windows 7 64bit and one with Windows Xp 64 bit. The game installed without a hitch on windows 7 but I was getting the startup error on the windows xp box. When I looked at the directories between the two, I noticed that for some reason the installer was not placing ALL the files on my windows xp box and thus tossing this error. I'm not sure why it was doing it. Luckily though, the solution was to simply copy over the entire folder from my windows 7 box to the windows xp box for the expansion that was causing the problem and re-install from there.
I don't know if this is an issue where the digital copy isn't pulling down the entire package or if its an issue where the installer just isn't placing everything out there. I realize this isn't a solution for you but maybe the EA people will be able to look into this and verify. At the very least you should be able to verify how many files are being placed in your new expansion folder. There should be a lot of files in there.
