Problem with dynamic lights

[Devil's doll]

I supouse that this is a configuration problem because I download a demo wad form here (first reply):
http://forum.drdteam.org/viewtopic.php?t=2536
and it still looks horrible.

Look this imgage, taken from that demo wad. There are only two dynamc lights things but it looks like dozens. What is happening?

[Nash]

Looks like you have an old graphics card that doesn't do texture clamping properly.