When I have Parallels running and I insert a DVD it won't even show up in finder. It will automatically try to play the DVD in XP... once I quit Parallels it will (after a few more seconds) show up in Finder and DVD Player will open.
I'm sure there's something I can change in the Parallels settings, but I can't fiqure it out.
I would guess the ties Parallels Tools creates with your hardware result in a conflict of sorts. It appears the virtual machine becomes the dominant hardware controller.
If you need to run Parallels frequently, try quitting it while the virtual machine is running. Don't shutdown the guest OS; simply quit Parallels. I've noticed carrying out this process allows the guest OS to be immediately available upon launching it from my Dock shortcut. Perhaps this will allow normal DVD play in the Mac OS without the need to completely shutdown the guest OS and Parallels.
You should check the parallels settings to see if you can set the default behaviour. Have Parallels set to not engage the DVD drive. You can then choose to have the drive captured from within Parallels as needed.
“Maybe some day somebody will call me "Sir" without adding "You're making a scene"!!”