The Radeon LE normally does support OpenGL just fine.
Most likely you have some sort of corruption with the OpenGL portion of your driver. You may have missed deleting an old OpenGL file that your previous video card used, and it's screwing up your OpenGL support (either the game or the video card may be trying to use the old driver file instead of the proper ones).
And as the above poster mentioned, you may want to try a more recent driver; the Win2K drivers are up to version 3210 (a link is available at Rage3D.com).