diff --git a/include/class_ldap.inc b/include/class_ldap.inc
index 5bde7ed04a0d197dc74ee87ab61b90e648194e62..f1bc05ec5c9051786cd13d8c221b330fbf3f3897 100755
--- a/include/class_ldap.inc
+++ b/include/class_ldap.inc
@@ -943,7 +943,7 @@ class LDAP
       if (!$this->dn_exists($cdn)) {
         $type   = preg_replace('/^([^=]+)=.*$/', '\\1', (string) $cdn);
         $param  = preg_replace('/^[^=]+=([^,]+).*$/', '\\1', (string) $cdn);
-        $param  = preg_replace(['/\\\\,/','/\\\\"/'], [',','"'], $param);
+        $param  = preg_replace(['/\\\\,/','/\\\\"/'], [',','"'], (string) $param);
 
         $na = [];
 
@@ -1106,7 +1106,7 @@ class LDAP
   {
     $ret    = [];
     $url    = preg_replace('!\?\?.*$!', '', (string) $url);
-    $server = preg_replace('!^([^:]+://[^/]+)/.*$!', '\\1', $url);
+    $server = preg_replace('!^([^:]+://[^/]+)/.*$!', '\\1', (string) $url);
 
     if ($referrals === NULL) {
       $referrals = $this->referrals;
@@ -1500,13 +1500,13 @@ class LDAP
 
     /* Remove ' and " if needed */
     $value = preg_replace('/^[\'"]/', '', (string) $value);
-    $value = preg_replace('/[\'"] *$/', '', $value);
+    $value = preg_replace('/[\'"] *$/', '', (string) $value);
 
     /* Convert to array if $ is inside... */
-    if (preg_match('/\$/', $value)) {
-      $container = preg_split('/\s*\$\s*/', $value);
+    if (preg_match('/\$/', (string) $value)) {
+      $container = preg_split('/\s*\$\s*/', (string) $value);
     } else {
-      $container = rtrim($value);
+      $container = rtrim((string) $value);
     }
 
     return $container;