I've experienced this myself, but now two other customers have reported the same error: the game runs fine in a window, but if you try to run it full-screen with two monitors it crashes with this output:
X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 144 (GLX) Minor opcode of failed request: 5 (X_GLXMakeCurrent) Serial number of failed request: 133 Current serial number in output stream: 133 Locking assertion failure. Backtrace: #0 /usr/lib/libxcb-xlib.so.0 [0xd8d767] #1 /usr/lib/libxcb-xlib.so.0(xcb_xlib_lock+0x2e) [0xd8d90e] #2 /usr/lib/libX11.so.6 [0x5d7c109] #3 /usr/lib/libGL.so.1 [0x637f792] #4 [0xd7fbf98]