use strict;
my $dir = "C:/some/dir";
my $script = "C:/path/to/csv2xls1.pl";
my @files = glob("$dir/*.csv");
for my $file (@files) {
    print "Processing $file .....";
    my $ret_val = system( $script, $file );
    print ret_val == 0 ? "OK\n" : "Not OK\n";
}
print "Done!\n";