Strange, I haven't seen that yet, and there's very little info. I do have Classic running on Win 7 x64, so I too know that it works. Do you perhaps run in a limited user account? Possibly try uninstalling, making sure all install files are removed in /Program Files/, then reinstall, running the installer with admin privileges if possible, and/or try running the executable with admin privs.
If none of that helps, I'm at a bit of a loss. Perhaps you can find a log with more info.
- Oshyan