Don't worry about it. We all start somewhere. It's nice to see that you've understood the basic concepts of level making. You did, however, use CEIL5_2 as a flat (floor/ceiling texture), which is the default flat in DoomBuilder I believe. That flat doesn't exist in SRB2's resources. The game's console will alert you when it finds a texture that doesn't exist. You should be able to see it at the level start, but if you don't, just press the tilde key (`), which is to the left of the 1 key. This will let you see errors as well as other important messages. It also lets you quickly carry out tasks such as name changing or setting the score limit in a netgame.
You also placed some upper-textures on the ceiling. Generally, it's a better idea to use a middle-texture and lower the ceiling height for that one sector, so you can collide with it.
One more thing. We like to use proper naming conventions for our maps. This is a match map, right? You should add the prefix m_ to your map's filename.
