is this the type of problem you are having?
Entity 10, Brush 0, Side 5: has a coplanar plane at (-753, -9, 251), texture CA1X_CON1B
Entity 10, Brush 0, Side 6: has a coplanar plane at (-753, -32, 251), texture CA1X_CON1B
I assume you are using Zoner's Compiling Tools. Because any problem you have while compiling can be answered in the Zoner's Help files.
If you dont have them, you should get them!, and the reason you are getting that problem is because there is a brush or brushes somewhere in your map that have two faces that are on the same plane. ie, there are two faces that look like one flat face. This is caused by vertex manipulation.