I am used to run XAMPP, a free and easy-to-install distribution of Apache, MySQL and PHP, on my computer to develop server-side web applications. I don’t need it regularly, but it’s a handy tool if you’re not so much interested in thousands of config files.

For some weeks now, I am unable to start Apache, which is cancelling with a socket error. Up to now, I didn’t track the problem and did my development directly online (urgh, bad style). Today I uninstalled the whole package and installed the latest version – and still got the same problem. So I had to ask Google (and the XAMPP forums) finally.

The problem was solved very quickly: It turned out that Skype, the VoIP solution of my choice, blocks port 80 (yeah, the common HTTP port). Since I updated Skype, I let it start together with Windows (I use it really often right now), therefore causing the problem. So you either have to stop Skype while using XAMPP, or tell Skype not to listen on port 80.

Troubleshooting with Ralf, problem solved.
Have a nice weekend!