OK.. I seem to recall there was something weird going on when the CD 2 was used as a key (as it would be if you wanted AZR terrain). If I recall correctly, it turns OFF Autoplay (though it shouldn't affect FINDING the CD). If it was CD 2, then try with CD 1 and see if it puts it to rights.

Even better... get hold of Daemon Tools, rip an .iso or .nrg from your LB2 CD's and store them somewhere where Daemon tools can mount them. Map updates are ultra quick and no need to swap CD's around in the drive and risk damage.