moving a model from pro desktop to 3dsmax 8

[Amittt]

I need to move a model built in pro desktop 8.0, a complicated one which was built from a lot of models attached. I wanna make an animation out of it.

Ok, look. when I import a .STL file it shows me a message:
"bla bla bla design1.stl is not a valid *.STL file"
This file was exported from autodesk pro desktop 8.0 in this way:
File --> export --> browse --> choosing the file --> save --> ok.
if you can help, pleaseeeee...

Ok, now I tried a diffrent file type: *.IGS
I exported it from pro desktop 8.0 in the same way and imported it in 3ds max.
A simple object like a square was imported perfectly to 3dsmax 8, but when I tried importing a complicated structure like a base of a robot (which was built from several other designs which were connected to one design) it didn't import nothing.
Please, if you dont know how to help, please ask people around you : )
Or you can main an answer to lm.robotica@gmail.com
Tanks.

Thanks a head, animation team, 1578.