RS logix500 config I/O problem

I'm sure theres a simple answer for this but I can't find it.

I'm using RSlogix 500 Ver6.20
the PLC is a 1747 5/05

I have the program for a machine on my desk-top.
I can look at edit and add I/O to my hearts content.
But when I save the program to a memory stick, put it on my laptop and try to edit the i/o I can't.
It does not show full rack. It shows the machine as having a 2 slot rack and not the 13 slot rack installed.

I've saved the progam 3 times now on the desktop, opened it on the laptop with the same result.

Whats going on?

Are both version of RSLogix500 the same?

No, desktop is 7.10 laptop 6.2.

But Ive copied over other machines programs and they dont have this IO problem they show the correct IO.

I think there is a work around. I can't remember if you open the project in a text file and change the version information or if it involves doing a save as to the library file .SLC or none of the above.
Can you upgrade your laptop software?