MX3 problem

I have to say I thought being able to write programs for about any
mill and make that baby sing while cutting was everything, boy was I
stupid. You guys out are making CNC mills, lathes, routers, EDM's,
and etc. from the ground up, PCs boards and all, is supercool and I
congratulate you all.

Heres my problem. I program in Bobcad, save to a disk, then load it
into my mill. The mill will do any 2 1/2D work, such as pocket to
certain depths, drill holes and etc. It's just when I do a 3D job,
such as a dome or a contour that it won't read the program without
some kind of fault coming up on the screen. Now I can program 3D
directly on the mills screen and it will do fine. Now I was told that
running a DNC cable via RS232 the mill would do 3D work.
The MX3 does not read standard G-codes in conventional terms (thanks
Jon), but changes them to events.

Question 1. Can the inital parameters of be of the hard drive be
changed to accept G-code?

Question 2. What's the difference between RS-274D and RS-232?

Question 3. Or does anyone have any suggestions around this problem?

Thanks: Scott Warden