Attempted to download itunes version 10.3.1 for 64-bit Windows Vista and get an error when trying to open itunes after a supposedly successful download.
"The iTunes application could not be opened. An unknown error occurred (-50)."
Apparently version 10.3.1 was supposed to fix this error. Any ideas???
... maybe it's becoming a higher-percentage play, nowadays. (The -50 is a fairly generic time-out message, so the most common underlying causes of it tend to change over time.)
If your current user account is an administrative account already, it's possible you're had a permission go strange here for a file or folder or a registry key. It's always a bit tricky to tell what permission is awry with one of these, so I generally try to avoid "fixing" things for fear of mucking something else up ... So if you don't want to have to do a "Run as administrator" every time you want to launch iTunes, you could set iTunes to automatically launch as an administrator (so you can then launch it "normally" but it will do a Run as administrator).
To do that, right-click your iTunes.exe again, but this time select "Properties". In the compatibility tab, check the "Run as administrator" box and click OK.