I'm kind of at a loss myself. I can't reproduce it.
Just for the heck of it, I'm curious what happens if you put MinGW's bin directory in your path. You'd have to add it, then launch a console, and then launch SlickEdit from there (I guess running SlickEdit from an icon would work too). You can be sure it worked by running the command "set" on the SlickEdit command line.
I'll ask some colleagues later today. It's only 645am here on the East coast of the US, so it will be an hour or so before I expect to see anybody else online.