Information you should include when asking questions

If you run into issues with UNetbootin, try using the version available on http://unetbootin.sourceforge.net/ if you obtained it from a different source (your version may be outdated). If the problem still persists, take note of the version of UNetbootin you're using (it's in the filename if you downloaded it from here), the ISO file you're installing or the distribution you're letting UNetbootin download for you, and the OS you're on (like "Windows 7, 64-bit" or "Ubuntu 10.04, 32-bit") when asking the question.