EMC Glitch?

I wonder if any of you EMC Gurus out there can riddle me this:
When I load a program into EMC, and machine something, everything is
cool, but when I try to load another program without leaving EMC, I
get an error window something to the effect of "No Permission". I
can't seem to get around the error, so I have to restart EMC, re-
home my axes, and then load the next program. No huge deal, but it
is an inconvenience. Just trying to figure out if it is something
with my file system, or a glitch in EMC. Any advice would be
appreciated.