on Mac OS X... you need to do 1 of two things... 1. install Xquartz 2.6.0 (if the 10.5 package is available yet, or you can build it off Macports). This has some RandR support for changing resolutions and fullscreen stuff... earlier versions do not, and that error is very common.. and it isn't lying to you, the mode really isn't available without RandR support. 2. On any X11 version, just go in winecfg and enable a virtual desktop... the game will see that virtual desktop window as its fullscreen and be able to adjust resolution (modes) correctly by just resizing the window. either of those 2 should fix the problem, but option 2 will force you to always have it running in a window.
