I would see this problem occasionally also. (both on Mac and Windows) all the advise in the Megaten forums talk about removing your temporary internet files, which do not exist in CrossOver as such.
I found that waiting and updating later seemed to fix that. But of course it is a pain.
If you want to play without updating do these steps:
1) go to Programs->Run Command...
2) Click on the dropdown "Debug Options"
3) click on "Open Shell"
4) when the shell is open and ready (give it a few seconds to get to the command prompt) type
cd AeriaGames/Megaten
5) then type
wine ./ImagineClient.exe
Of course any file that failed to update will not work. So in your case your CompStore will not work. But at least you can play until it gets sorted out.
I am not sure why it happens but it looks like Megaten downloads a hash file and somehow that hashfile gets cached somewhere and so the number stop lining up. I do not think it is a CrossOver Mac issue but it is annoying never the less.
-aric