I have a Marantz player that occasionally spits out discs when it's first powered up. In addition to the above suggestion to turn it off, wait a minute, and then turn it back on - here are some other things:
1. Close the drawer with the remote, and if it pops back out, use the button on the faceplate.
2. Push "Play" instead of Close on the remote. If that's what you were doing anyway, push Close first and then Play in rapid succession.
3. Push the tray in with your hand (gently!) - about halfway in, the motor should take over and lock it in place
Once the disc stays in, the display should show the number of tracks, and the remaining time.
These are tricks I use with the CD67 SE, which is an old model. Usually once you get it to work, it'll work fine from there out...until the next time.