I doing exaclly what is being asked but i'm getting problems.

On this part:
- Start a Maya session, and open the script editor, then type source GI_Joe. Press [enter]
Retype GI_Joe and press [enter] to execute the script.
You can then drag the GI_Joe into your shelf and select the GIJoe_icon as shelf icon.

I'm doing the part "type source GI_Joe but i get this message:

source GI_Joe;
// Error: source GI_Joe; //
// Error: Cannot find file "GI_Joe" for source statement. //

Am i doing somthing wrong?