Version 5.0.6

system/Lang/Lang.php

@@ -1676,11 +1676,15 @@ class Lang extends Model
 
 				/* @var cms\Fields\ $fieldsClass */
 				$fieldsClass = '\IPS\cms\Fields' . $database['database_id'];
-				$customFields = $fieldsClass::databaseFieldIds();
-
-				foreach ( $customFields AS $id )
+				
+				if ( class_exists( $fieldsClass ) )
 				{
-					$this->words['sort_field_' . $id] = $this->addToStack( 'content_field_' . $id );
+					$customFields = $fieldsClass::databaseFieldIds();
+
+					foreach ( $customFields AS $id )
+					{
+						$this->words['sort_field_' . $id] = $this->addToStack( 'content_field_' . $id );
+					}
 				}
 			}
 		}