error MAX_TW_VERTS (12) exceeded??? help

[e)G-Destructo]

when i compile the map with lights it gives me this error i just added a few things to this one room it workd before i did those but it wasnt any lights

--- SetupTraceNodes ---
************ ERROR ************
MAX_TW_VERTS (12) exceeded

[Jadocran]

You may have a brush, that intersects too many other brushes. Try to delete it or divide it into smaller brushes.

Please use Search before posting.
And also try Google it.