Newb mapping issues

[Solarn]

So yeah. I'm new here and I only just started mapping for Quake using QuArK and I wanted to make a small single player map first. Since any links to tutorials I found were dead, I had to learn everything the hard way, but I managed the basics somehow and I can now generally make a map without any leaks (although I still had to encase this one in a giant box because there was a leak I couldn't find). But there is a problem. I currently have a starting room and a short corridor leading away from it and there's something wrong with the corridor. When I start Quake (I use FitzQuake 085) and load the map, the far end of the corridor looks similar to the Hall of Mirrors effect in Doom, which happens there when an untextured line is seen. I can't describe it any better. Basically, it retains an image of whatever was there on the screen before and sort of smears it all over that part when I move. Here's the map, so you can see for yourselves what I'm talking about (the .map file is the one I have to upload so you can take a look at it, right?). I have no idea why this is happening and I want to know what I need to do to fix it. Please help me.
Here it is.

[Baker]

Although you might get someone posting some mapping help in the thread, the core of the Quake mapping community lives at Func_Msgboard: Latest News and the Mapping Help thread at that site is a great place to post questions like these.

[Solarn]

Although you might get someone posting some mapping help in the thread, the core of the Quake mapping community lives at Func_Msgboard: Latest News and the Mapping Help thread at that site is a great place to post questions like these.

Thank you. I didn't know of that site, it does look good for someone looking for mapping help.