Bruno,
I see Don has explained the ARC thing for you, but I thought I'd add a little
about Aterm. It exists in DL 4 in two forms… one is the executable, and the
other is ARCed (they end with .EXE and .ARC, respectively). If you have the one
that ends with .EXE you don't need to run ARC on it.
Regards, Larry.