I have come across this before when copying the .mn* files and button icons to another machine.
It was a problem with the NAMES of the icons not the location, especially if you have given them your own name rather than the Acad generated one.
As you say when you start Autocad after copying the mn* files and button icons you often get smiley faces insted of the image.
The only way I found to correct this is to edit the button in Autocad and reload the the image back in.
PS. This applies to the older Autocad versions that use the drop down menus and .mn* files; not to 2006+ that use the CUI.
Last edited by NukeCad; 22-01-2013 at 12:51 PM.
Im intelligent enough to know that I dont know everything; but I'll tell you all about it anyway.