Samba's "net" command is /usr/bin/net on all Fedora/RHEL releases.

--- smbldap_tools.pl
+++ smbldap_tools.pl
@@ -243,7 +243,7 @@
 my %smbconf = read_smbconf();
 
 sub getLocalSID {
-    open my $fh, "-|" or exec("$samba_bindir/netx", "getlocalsid") || exit(1);
+    open my $fh, "-|" or exec("$samba_bindir/net", "getlocalsid") || exit(1);
 
     my $line = <$fh>;
     if (!defined($line)) {