Zero problems on my pc - just printed a report to be sure too.
If you look at the Quicken site, they say they only support 2010, but like I said no problems at all.
I have yet to come across a program I used on Vista that won't work on 7. Windows has built in compatiblity settings to change if you need to also.
Here is another screen from File/Open:
On your scenario you mentioned, I think I would question whether or not the program was ran with administrative rights, like maybe they did not have full access.
To prevent this, when you run the program, right click on it and select 'Run as Administrator'.
I would do the same thing with the installation - if you have the download or cd, find the setup.exe installation file and run as administrator to install.
You shouldn't have any trouble.