Texture Offset Issue.

[Mega_Man]

I'm trying to line up some textures when i come across this strange problem. The textures are only as tall as the ceiling hight. They don't loop like the others do. It's hard to explane so i linked pictures.
http://i56.photobucket.com/albums/g193/somethingsometh/map3.jpg
http://i56.photobucket.com/albums/g193/somethingsometh/map2.jpg
http://i56.photobucket.com/albums/g193/somethingsometh/map1.jpg

it problem vanishes when i uncheck the back side. However i need that back side.

This whole problem started when i drew a large sector around the map.

[Dr. Zin]

That is because you are using poor mapping technique, using a two-sided line as a wall. Mid-textures on two-sided lines do not tile, as they are mostly used for railings. I would suggest reading some mapping guides to learn what to do and what not to do.