Compiling DMD on MAC OS X

[Tyro[a.c.edwards]]

Hi all,

I've just installed DMD 2.058 and attempted to compile a little 
script but was greeted with the following error:

gcc: Invalid argument

I used the .dmg installer from http://www.dlang.org/download.html 
and issued the command:

dmd average

Is there something I'm missing?

Thanks,
Andrew