rgbPatch.txt is a file you add to the rgb.txt which comes with MI/X. It provides some color names and aliases used by vim, so that vim can do syntax coloring of Perl properly. You need neither .Xdefaults nor ~/app-default/vim.
You can redistribute all my programs, and/or modify them, under the terms of
The Perl License, a copy of which is available via: http://dev.perl.org/licenses/