Anyone know Tomcat?

Unfortumately I am pretty much clueless about Tomcat or what it does/is.

But my friend was doing some programming within it. Anyway, he changed some network settings on his computer (after which it was no longer connected to the internet), and the program stopped working. You could click on 'startup.bat' and the tomcat DOS window appears briefly then vanishes.

Will simply reconnecting to the internet fix it, or can he reinstall the program and copy his programming back in?

Like I say, I have no idea how this program works, or how widespread its use is, but seeing as there are a few IT experts here, I thought someone may know a solution.

Withough knowing what's in the bat file, I have no idea. But tell him to execute that bat file at a command least then he will be able to see the error messages and know where the problem is.

Thanks for the quick reply. If I got him to post the bat file would that help? I believe it says network not detected or something.