File Header and Unable to Delete Errors

[Imp]

Just a thought here but why are you doing it that way in any case.
Extract the new campagins to a folder called say temp.
Start Campaign Hack nav to that folder & renumber them.
Now just copy them into your campaign folder.

Cant see the files becoming read only unless you mucked about but as someone said if you accepted default install to programs the system could be hiding the files.

Either way doing a fulldisk check would not cause any harm as would say thats your other problem.
Best done overnight unless you have a small drive