probs with unit importing

[iroin0]

i did what the tutorial said but instead it said 'could not load file blah blah blah'. it also comes up green cube not purple like it sais. i hope it not cous i got mac . thing is, it doesnt be like that when i use attachments, only units.
odd?

plz someone help me im really stuck and if you could help it would well be apreashiated. soz about spelin iam pafetic
also i just found out is that they show up fine as .mdx flies on importer, but when binding to and object they show as .mdl oddly. i tryed changing the file on custom file instead of imported but it wouldnt let me and just stayed as mdl!

 

[Longvie]

What model are you trying to import?

 

[iroin0]

it does it with all i try to