Here a solution for this problem problem with new Wii's, some people load the game disk and play's fine and when it went to load another game. no response from the eject button. so stuck with the disk in.
BUT... frustration wins the day.
Hit the eject button fast " and i mean fast for about 50 times " and hey presto the CD ejected!!!!
it seems that the command for eject is not getting to the system and by doing this it manages to see the command at some stage.
Also Spoke with Nintendo tech support and they claimed if this did not work the front faceplate could be removed and there should be a pin hole for a paper clip behind the faceplate on the drive its self to do a manual eject with a paper clip.
hope this helps