Line/light glitch issue

Hey all,
On most of the maps, with the exception of gm_flatgrass and gm_construct, there have been these ‘lines’ appearing on most of my maps.
At first I thought it was a graphic issue, so I changed all the graphics settings to low, but it did not work. Then I realised that the lines change with the fog and light colour, even with the glowsticks weapon addon. They also randomly appear and disappear when you move.

http://img812.imageshack.us/img812/5056/53633195.jpg
http://img43.imageshack.us/img43/2592/61833704.jpg

Anyone else have this problem? or know how to fix it?
Thank you! <3