I don't think you stated but any chance your m/b uses the nVidia chipset?

Note this might be a red herring (as i took a very quick skim through thread) Error Flushing Device Cache Error & Locked Tray. Seems there are some eerily simliar situations (at least where CDBurnerXP fails yet Nero works) and i think a couple who fixed their problem related it to the nVidia chipset.

But, again, i'll warn i took just a quick skim. I'll let you look closer if you want to see if any cases relate at all to your situation