diff --git a/Repositories/otago_eprints3/otago_eprints/cfg/cfg.d/twitter.pl b/Repositories/otago_eprints3/otago_eprints/cfg/cfg.d/twitter.pl
index cf3f4b4..b124706 100755
--- a/Repositories/otago_eprints3/otago_eprints/cfg/cfg.d/twitter.pl
+++ b/Repositories/otago_eprints3/otago_eprints/cfg/cfg.d/twitter.pl
@@ -13,6 +13,7 @@
                 
 		my $isgdCmd = '';
 		my $twitterCmd = '';
+		my $urlCmd = '';
 		my $shorturl = '';
                 
 		my $title = $eprint->get_value( "title" );
@@ -24,25 +25,29 @@
                 
 		SWITCH: foreach ( 'curl', 'wget' ) # add others here and below
 		{
-			# Try to call the command, if it's not in the path then $?
-			# will be -1 and $! will be 'No such file or directory'.
-			# If nothing works, just fail silently.
-			system( $_ );
-			if ( $? != -1 )
+			# NJS 2010-01-12: Changed to use which instead of $? value.
+			# Check that the command exists using which. If it exists
+			# then the output of which will start with '/', otherwise
+			# it won't (it will usually be empty or something like
+			# "no such ..." or "foo: not found")
+			$urlCmd = `which $_`;
+			chomp $urlCmd;
+
+			if ( $urlCmd =~ m|^/|  )
 			{
 				if ( /curl/ )
 				{
-					$isgdCmd = "curl --silent 'http://is.gd/api.php?longurl=" . $eprint->get_url . "'";
+					$isgdCmd = "$urlCmd --silent 'http://is.gd/api.php?longurl=" . $eprint->get_url . "'";
 					$shorturl = `$isgdCmd`;
-					$twitterCmd = "curl --silent --basic --user $twitter_username:$twitter_password --data status='$title - $shorturl' http://twitter.com/statuses/update.xml";
+					$twitterCmd = "$urlCmd --silent --basic --user $twitter_username:$twitter_password --data status='$title - $shorturl' http://twitter.com/statuses/update.xml";
 					`$twitterCmd &`;
 					last SWITCH;
 				}
 				if ( /wget/ )
 				{
-					$isgdCmd = "wget --quiet --output-document=- 'http://is.gd/api.php?longurl=" . $eprint->get_url . "'";
+					$isgdCmd = "$urlCmd --quiet --output-document=- 'http://is.gd/api.php?longurl=" . $eprint->get_url . "'";
 					$shorturl = `$isgdCmd`;
-					$twitterCmd = "wget --quiet --http-user=$twitter_username --http-password=$twitter_password --post-data='status=$title - $shorturl' http://twitter.com/statuses/update.xml";
+					$twitterCmd = "$urlCmd --quiet --http-user=$twitter_username --http-password=$twitter_password --post-data='status=$title - $shorturl' http://twitter.com/statuses/update.xml";
 					`$twitterCmd &`;
 					last SWITCH;
 				}