This exactly happens to me too. Whenever you are prompted that 'wrong volume' message, just put CD1 (play disc) into your drive, and press 'retry' (or 'ok'). Last time I installed the game, I got the message 3 times, and all the times I made it disappear feeding it CD1. Hope that works.
- E D I T -
+ Note that this didn't happen at all the first time I installed the game upon its release, months ago.
+ Also note that I have just uninstalled the game due to the unbearable amount of crashing it was going thru (at random, but quite often: once every less-than-5-minutes), and am going to reinstall it from scratch.
+ Note that when I originally played the game I didn't experience any issue, beside the 'Dantooine FPS Slow Down', which could be easily fixed (can't remember how, tho).
+ Thus my 'fix' could not be working at all.