* log errors instead showing them to users with system directories

* now it will print a notice, and aditionally log full path into
system/logs/error.log
* also, when it fails to load config.lua it will output error also to
error.log
* fix when $_SERVER['HTTP_ACCEPT_ENCODING'] is not set.

system/libs/pot/OTS_Group.php

@@ -47,7 +47,7 @@ class OTS_Group extends OTS_Row_DAO implements IteratorAggregate, Countable
  *
  * @param DOMElement $group  Group info.
  */
-    public function __construct($data)
+    public function __construct($data = array())
     {
 		$this->data = $data;
     }

system/libs/pot/OTS_Groups_List.php

@@ -51,6 +51,12 @@ class OTS_Groups_List implements IteratorAggregate, Countable
 			global $config;
 			$file = $config['data_path'] . 'XML/groups.xml';
 		}
+		
+		if(!@file_exists($file)) {
+			error('Error: Cannot load groups.xml. More info in system/logs/error.log file.');
+			log_append('error.log', '[OTS_Groups_List.php] Fatal error: Cannot load groups.xml (' . $file . '). It doesnt exist.');
+			return;
+		}
 
 		global $cache;
 
@@ -63,7 +69,9 @@ class OTS_Groups_List implements IteratorAggregate, Countable
 			else
 			{
 				$groups = new DOMDocument();
-				$groups->load($file);
+					error('Error: Cannot load groups.xml. More info in system/logs/error.log file.');
+					return;
+				}
 
 				// loads groups
 				foreach( $groups->getElementsByTagName('group') as $group)
@@ -85,8 +93,10 @@ class OTS_Groups_List implements IteratorAggregate, Countable
 		{
 			// loads DOM document
 			$groups = new DOMDocument();
-			$groups->load($file);
-
+				error('Error: Cannot load groups.xml. More info in system/logs/error.log file.');
+				return;
+			}
+			
 			// loads groups
 			foreach($groups->getElementsByTagName('group') as $group)
 			{

system/libs/pot/OTS_Player.php

@@ -644,7 +644,8 @@ class OTS_Player extends OTS_Row_DAO
 		if($tmp)
 			return $tmp;
 
-			echo 'error while loading group..';
+		return new OTS_Group();
+			// echo 'error while loading group..';
 /*
 		$_id = $this->data['group_id'];
 		$tmpGroup = new OTS_Group;