rpallen wrote:I really have no idea what this means
That message means, that Port 80 (which is used by Apache) is already in use by another process. You have to find out, which process causes this. Normally, there are only a few possibilities for that:
a) you have a skype installation up and running. Do you? If so, enter the Skype Options Menu and configure Skype NOT to use Port 80.
b) you already have an Apache installation up and running. Enter "ps -fe" in a shell (terminal) and watch out for "Apache", or "apache" (or "Apache2" or similar) or "httpd".
If you already have an Apache installation, go to the System Menu of Linux Mint and start the Software Installation tool and try to find the corresponding package, if you find it choose de-installation and finally reboot your PC. Then try again to start Xampp.