Error Message, When Trying to run Ubuntu

[Richie Gardenhire]

Hello, When I went to try and run Ubuntu on my iMac, I got an error  
message that said, "This program cannot run DOS on this machine."  Is  
there a component that I'm missing?  I am running Fusion, too.  I  
understand, however, that it's not necessary to have Fusion running;  
Ubuntu should be a straightforward installation, should it not?   
Richie Gardenhire, Anchorage, Alaska.
Skype: alaska_mac_attack.