I own an iMac and don't have that error. This should no happen and you should look into memory allocation before you next start it up.
Im thinking of buying a imac g5 but I don't know if I can run Minecraft on it
Yes, the iMac is more then capable of playing Minecraft. It's the internet connection speed that will be the bottle neck when playing multiplayer.
Reboot means to restart. To restart or reboot click the apple icon top left and then click Restart.
No, the iMac will not play a Blueray disc.
If you want to play it, then go ahead! The game was written in Java, so all you need is the Java VM, acquired when you install Java.
No. You can only play games made for Mac OS on an iMac.
There is no Mac version of Maple Story but if you have a recent iMac with an Intel processor than you can run Windows on your iMac and play the Windows version of Maple Story - see related link below for details.
To fix your iMac if you can't use the bootcamp partition, reboot it and check the install logs.
there is no way to play minecraft as a guest.
Minecraft has a rating of E10+, so any kid of 10 and older can play Minecraft.
Yes
No it will not play a 6" disc. It will play a CD or DVD.