Unable to Play Zero Hour

I am unable to load my Challenge progress in Zero Hour - whenever I try to the loading screen comes up for the General vs General but then it immediately says "Defeated".

I'm playing the game through the EA App and it's the full licensed version of the game (no cracks, illegal copies etc). I've never had an issue until went to play it today (save file is from 4 month ago), when the game closes I get a prompt that some files are corrupted and the app offers a repair. 5 times I've repaired so far and still it's a problem.

I've already attempted the license key "fix" of adding the dashes into the default key under HKLM\SOFTWARE\WOW6432Node\Electronic Arts\EA Games\Command and Conquer Generals Zero Hour\ergc but that hasn't fixed it. I've also tried modifying my options.ini file as I've seen in places online but still no joy :-(

EA doesn't seem to offer support for this title according to the list of games to raise issues with via their site so I'm hoping that someone can advise what is going on and how I can fix this...