Rhino has an option to choose between saving NURBS object or polygon mesh objects into an OBJ file.

But the vast majority of programs only expect to see polygon data in an OBJ file. So if they used the option to write NURBS that could be the problem.

Also I seem to vaguely recall that there is also an option to break up long lines of text and if that's enabled that can also mess up some programs as well.

So it could be related to the specific options that they are choosing at export time.

- Michael