I have exactly the same problem. My install CD is the UK version, v1.03. I am running Windows XP. CD drive is Relisys 16x DVD. I have installed v1.12 and now the game refuses to see the CD-ROM. I have uninstalled then re-installed from the original CD, now v1.03 will not read the CD either.
I have tried another CD-ROM drive, same problem.
It's quite obvious that COMBAT MISSION has a problem, NOT our hardware. Seems like a fix is required from Battlefront don't you agree ??