[Duke461]

You have to be very careful with editing the full robot assembly. two people should never have the same file up unless they are very experienced. on top of that, be careful with changing files. You should be fine as long as those file locations aren't put in a place not everybody can reach them, otherwise it wont load the parts and assemblies you need. So for instance, we have at our school what's called a Y drive, a student common drive, and a Max drive.
The Y drive is every students personal "folder". The student common is a drive that everyone can access, and the max drive is for robotics people only. So lets say Bob is CADding the arm assembly on his "Y" drive, and then when he's done, he transfer the assembly file to Joe's flash drive. Joe will not be able to load that file because the parts making up that assembly are located in Bob's "Y" drive. But if Bob saves everything into the student common or Max Drive, even if you only have the assembly, inventor will recognize this and try to help you locate the parts, which you could do if they were in a "student common" folder.
Hope this helps,
if this wasn't the answer you were looking for or if you have any others questions, just ask,
good luck,
-Duke
P.S. i understand what he's going through, i've CADded almost the entire robot myself this year also using Autodesk Inventor 2011; so i can answer very specific Autodesk questions as well.