Compatibility issues with Windows Vista

[Oopser]

I am testing our software on compatibility with Windows Vista, using Vista build 5365. While trying to run "Check for Updates", I've got the following message: "This program has been damaged, possibly by a bad sector of the hard drive or a virus. Please, reinstall it". Sure reinstall did not help. The error message pops up right after start. I have local administrator rights on this PC. Internet is accessible.
Has anybody got similar problem? Any ideas?
Thanks.

[Ted Sullivan]

Have you tried this with TrueUpdate 2.0? Version 1.0 is no longer being developed, but v2.0 will definitely be Vista compatible.