Pioneer DVD-ROM will not eject after some time of system usage

I'm having an odd issue where after my Mac Pro works for a certain amount of time (it seems variable), the drive will no longer seemingly be recognized. It shows up in the hardware profile for the system, however when I hit the eject key, Toast starts up instead of my drive responding. Further, when Toast or any other CD / DVD writing utility is started, the drive is not recognized in these applications. Any idea as to what could potentially be going on here? The thing that throws me the real curve ball is that it DOES work for a little while when the system is restarted and then just "disappears" as noted. NOTE: Even when Toast is not in the mix Disk Utility and other apps will not recognize the drive. It is obviously some kind of an OS issue in terms of it still showing up in the hardware profile, yet no applications are able to detect / use it properly.