Make a quick stab at the "Open data reader" issue.

MySqlDataReader needs to be Close()d explicitly. Disposing it or letting
it fall out of scope will not free it's hold on the connection.

OpenSim/Data/MySQL/MySQLRegionData.cs

@@ -212,7 +212,10 @@ namespace OpenSim.Data.MySQL
         {
             MySqlCommand cmd = new MySqlCommand(m_waitTimeoutSelect, m_connection);
 
-            using (MySqlDataReader dbReader = cmd.ExecuteReader(CommandBehavior.SingleRow))
+            lock (m_dataSet)
+            {
+                MySqlDataReader dbReader = cmd.ExecuteReader(CommandBehavior.SingleRow);
+                try
                 {
                     if (dbReader.Read())
                     {
@@ -220,9 +223,13 @@ namespace OpenSim.Data.MySQL
                             = Convert.ToInt32(dbReader["@@wait_timeout"]) * TimeSpan.TicksPerSecond + m_waitTimeoutLeeway;
                     }
 
-                dbReader.Close();
                     cmd.Dispose();
                 }
+                finally
+                {
+                    dbReader.Close();
+                }
+            }
 
             m_lastConnectionUse = System.DateTime.Now.Ticks;
 
@@ -571,7 +578,8 @@ namespace OpenSim.Data.MySQL
             lock (m_dataSet)
             {
                 CheckConnection();
-                using (MySqlDataReader row = cmd.ExecuteReader())
+                MySqlDataReader row = cmd.ExecuteReader();
+                try
                 {
                     int rev = 0;
                     if (row.Read())
@@ -595,6 +603,10 @@ namespace OpenSim.Data.MySQL
 
                     m_log.Info("[REGION DB]: Loaded terrain revision r" + rev.ToString());
                 }
+                finally
+                {
+                    row.Close();
+                }
             }
             return terret;
         }