I'm pretty sure it works. I currently do not have windows vista because it fails. I have windows xp. Did you try to run it as Administrator? I'm pretty sure that normal users cannot write to program files. Try writing to documents instead? If writing to documents works and not program files, then it's your account limits that restricts you.

*EDIT*
For the file you are writing to, change it to: "C:\\Program Files\\resolution.txt"
I'm sure that Lite-C doesn't know where to open the file. If that doesn't work, then it's the problem I explained above. Oh, if you don't know why I have \\ instead of \, it is because strings have escape sequences. \n is newline, \t is tab, etc. And because of that, \ doesn't mean anything unless if you put a character in front of it. Which means you need \\ to have \ in the actual string.