diff --git a/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/ConnectionDirectory.java b/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/ConnectionDirectory.java
index bb85159db..c769530ef 100644
--- a/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/ConnectionDirectory.java
+++ b/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/ConnectionDirectory.java
@@ -173,7 +173,7 @@ public class ConnectionDirectory implements Directory<String, Connection>{
 
         // Verify that no connection already exists with this name.
         MySQLConnection previousConnection =
-                connectionService.retrieveConnection(name, user_id, parentID);
+                connectionService.retrieveConnection(name, parentID, user_id);
         if(previousConnection != null)
             throw new GuacamoleClientException("That connection name is already in use.");
 
@@ -329,7 +329,7 @@ public class ConnectionDirectory implements Directory<String, Connection>{
 
         // Verify that no connection already exists with this name.
         MySQLConnection previousConnection =
-                connectionService.retrieveConnection(mySQLConnection.getName(), user_id, parentID);
+                connectionService.retrieveConnection(mySQLConnection.getName(), parentID, user_id);
         if(previousConnection != null)
             throw new GuacamoleClientException("That connection name is already in use.");
         
diff --git a/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/ConnectionGroupDirectory.java b/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/ConnectionGroupDirectory.java
index 25e821b40..035c02bf8 100644
--- a/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/ConnectionGroupDirectory.java
+++ b/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/ConnectionGroupDirectory.java
@@ -156,7 +156,7 @@ public class ConnectionGroupDirectory implements Directory<String, ConnectionGro
 
         // Verify that no connection already exists with this name.
         MySQLConnectionGroup previousConnectionGroup =
-                connectionGroupService.retrieveConnectionGroup(name, user_id, parentID);
+                connectionGroupService.retrieveConnectionGroup(name, parentID, user_id);
         if(previousConnectionGroup != null)
             throw new GuacamoleClientException("That connection group name is already in use.");
 
@@ -273,7 +273,7 @@ public class ConnectionGroupDirectory implements Directory<String, ConnectionGro
 
         // Verify that no connection already exists with this name.
         MySQLConnectionGroup previousConnectionGroup =
-                connectionGroupService.retrieveConnectionGroup(mySQLConnectionGroup.getName(), user_id, parentID);
+                connectionGroupService.retrieveConnectionGroup(mySQLConnectionGroup.getName(), parentID, user_id);
         if(previousConnectionGroup != null)
             throw new GuacamoleClientException("That connection group name is already in use.");
         
diff --git a/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/service/PermissionCheckService.java b/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/service/PermissionCheckService.java
index 6cba01852..610ba437b 100644
--- a/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/service/PermissionCheckService.java
+++ b/extensions/guacamole-auth-mysql/src/main/java/net/sourceforge/guacamole/net/auth/mysql/service/PermissionCheckService.java
@@ -37,6 +37,7 @@ package net.sourceforge.guacamole.net.auth.mysql.service;
 
 import com.google.inject.Inject;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -161,7 +162,7 @@ public class PermissionCheckService {
      * @throws GuacamoleSecurityException If the specified permission is not
      *                                    granted.
      */
-    public void verifyConnectionGroupAccess(int userID, int affectedConnectionGroupID, String permissionType) throws GuacamoleSecurityException {
+    public void verifyConnectionGroupAccess(int userID, Integer affectedConnectionGroupID, String permissionType) throws GuacamoleSecurityException {
 
         // If permission does not exist, throw exception
         if(!checkConnectionGroupAccess(userID, affectedConnectionGroupID, permissionType))
@@ -440,6 +441,10 @@ public class PermissionCheckService {
         if(checkParentID) {
             // Get the IDs of all connections in the connection group
             List<Integer> allConnectionIDs = connectionService.getAllConnectionIDs(parentID);
+            
+            if(allConnectionIDs.isEmpty())
+                return Collections.EMPTY_LIST;
+            
             criteria.andConnection_idIn(allConnectionIDs);
         }
                                               
@@ -522,6 +527,10 @@ public class PermissionCheckService {
             // Get the IDs of all connection groups in the connection group
             List<Integer> allConnectionGroupIDs = connectionGroupService
                     .getAllConnectionGroupIDs(parentID);
+            
+            if(allConnectionGroupIDs.isEmpty())
+                return Collections.EMPTY_LIST;
+            
             criteria.andConnection_group_idIn(allConnectionGroupIDs);
         }