You may have noticed with Pro/E 2000i2 manufacturing code 2001140 that mapkeys will sometimes not work.  Even if you make sure the window is active, you may notice that only the first letter of the mapkey will show up in the bottom left hand corner of the main window.

This is a known bug with this version of the software and will be fixed in a later version.

In the mean time, you can work around this quite easily if you know how: simply click into the model window once with the left mouse button.  Then the mapkey should work correctly.