Hi I finally compiled my map thanks to MODSonline. But now I have another problem. my map loads up perfectly but when I walk out of my building i fall though my terrain and I'm walking around on my skybox and can only see the buildings I made.

You have likely textured the terrain w/ an alpha texture. You can identify them by the white outline around them in the texture window. Change to a non alpha (no white border), this should take care of falling through the ground.

Ok i tryed a brick wall and i still have the same problem

I assume you mean that you textured the ground w/ a brick texture, what is the name of this texture? (include the whole thing, this is important)
Also state what you made your terrain with (mesh, brush???).
Your not falling through a hole in the ground are you?
Did you make your terrain non-colliding?

In my original post that is the usual problem people have, but if that isn't it then we need a little more info to help ya out.
Later bud,

What does non-colliding mean? just curious... - Index

When you make something non-colliding it will not collide with anything, it will not stop bullets, vehicles, players, nothing. You can see them but they don't affect anything any other way.

As long as your terrain has a solid texture on it (with an "@" in the latter part of its name and not an "_" instead), and it's not non-colliding it should support the weight of the player.

To make sure your terrain is at least structural just highlight it all, right click on it in the 3D window, and select "make structural" from the little drop down menu.

So to make something non-colliding I understand, well say you have a plane they you can run through, how do you make it colliding? do you just make it structural? - Index

I know this isnt the right place to do it, but im a dork so...

To make any brushes or meshes colliding simply right-click it and make it "structural" or "detail". Also make sure that its texture is not one that makes it act non-colliding. Alpha textures do this. (Alpha textures of course being those with white borders around them in the textures window and with an "_" late in their name rather than an "@".)

If you are talking about a model though, either it's missing/doesn't have a collmap, or you could just place some clip brushes where it is, in it's general shape.

Ok the texture i used was [ground/a grass1] i then changed it to russia/floor/concrete@sewcrete_flat and still had the same problem i really wanted to use [ground/a grass1] texture in my map but if you could help me find a suitable texture i would be thankful. Iam am using a brush as the floor.

Thanks

Ok i managed to get the floor so i can walk on it but now i cant find a siutable texture for the level i want to make does anyone have any suggestions.

Thanks