Crap, wet firecracker, fizzle instead of bang.
That's expected, as each update and patch is installed it will overwrite previous files, so click Yes.
Start career, no joy - original USA campaigns only.
Here's the problem, instead of copying the German campaigns into the Campaign folder it installed in a separate CampaignGE folder. For whatever reason the game is not reading that folder. This is Windows XP Media Edition BTW, so it's not a Vista / Windows 7 UAC issue since there ain't no UAC in XP.