What I actually have that's now working is this:

RUN '\\print02\PCClient\win\pc-client.exe /silent'

The %comspec% worked but popped an error about trying to run a UNC path from a command line... No error this way.

But thanks for the reminder on the /c... I have to be more thorough when I post my examples and not just go from memory! Obviously that isn't working any more! LOL!

Mike