iTunes - broken!
I uppgraded my iTunes last night to the latest version (don't ask, I don't know the number). I followed the instructions to the letter because... well, I'm not a techy-geek so I wouldn't want to mess anything up.
Now I only get the dreaded:
Now... I am not at home - or even in my own country. If I reinstall iTunes will I lose all my music? What did I do wrong?
I don't have the definitive answer, but when you Google the phrase, "iTunes Cannot Run because some of its required files are missing", you will get a ton of responses. Most of them seem to suggest uninstalling the current version on your PC and starting over with the new version.
As far as your music, you might want to copy your music folder to another folder or thumb drive if you have one big enough.
I've done both reinstall and upgrade iTunes previously without losing any of my music - your music sits in its own folder (whether iTune's default or user specified, and in my case in several folders), so it should not be affected by a reinstall.
That said, I do have my music backed up to hard drive so that I can restore it if necessary. Alternatively, if drive volume is an issue, simply rename your iTunes music folder to something else. (Renaming a folder so that it becomes "invisible" to a program is essentially the same as copying the files to another directory and deleting the source.)