Thanks Weasel and everyone for the suggestions. The eval in a bare block turned out to be a nice, simple solution, and lets me catch more than just the possible error I know about:

sub dostuff {
    my $victim = shift;
    {
        eval {
            open IN, "$victim" or die "Can't open the file: $!\n";
        };
        last unless $@;
        if ($@ =~ /containing a running program/) {
            print "  Waiting...\n";
            sleep 5;
            redo;
        } else {
            die "Unknown error opening file: $@";
        }
    }
    # more stuff here
    close IN;
    rename "$victim", "/z/saved/$victim";
}
[download]

I'll have to get comfy with eval; I can see how it could be indispensable. Thanks again!

Peter