long story short your team mate needs to research inventor "projects" files
to be brief
inventor uses file associations to create the assembly file. think of it like this..
for purpose of example take this.
(graciously donated image from this thread..)
http://www.chiefdelphi.com/forums/sh...threadid=89768
assuming the chassis is one part. and the motors another, and the wheels a 3rd part
each of the parts needs to be save in the same folder within someones computer "directory" or drive so that the inventor project file can reference the location of the parts in the assembly .
to further simplify my suggestion is to require every part designer to save eery PART into the same folder and / or rather prior to "building" the robot in inventor to have all the parts saved (by the assembler) into the same folder
as you might have guessed we've had similar problems previously