when copying a exe-file like the new PuTTY.exe to our clients via DC, the users (and I) get a security warning like "The publisher could not be verified. Do you want to execute the Software?"

I can press execute but I cannot remove the checkbox "Prompt before every startup" without administrative privileges (folder is in C:\Programfiles)!

I already have added the DC Server to trusted Sites in Internet Explorer Security settings: "\\servername"

Does anyone have a good solution for this problem?

I have read about editing the registry to remove this security prompt for file extensions but this is a potentially high risk and not a good solution at all..