diff -ur chatroom/chatroom.module chatroom_new/chatroom.module
--- chatroom/chatroom.module	2007-04-24 08:24:11.000000000 -0400
+++ chatroom_new/chatroom.module	2007-07-04 15:27:47.938660061 -0400
@@ -695,11 +695,12 @@
  * gets a list of online users in a given chat
  */
 function chatroom_block_chat_online_list() {
+  global $base_url;
   if (!preg_match('/^chatrooms\/chat\/(\d+)/', $_GET['q'], $matches)) {
     return array(false, false);
   }
   $chat_id = $matches[1];
-  $cache_file = file_directory_temp() .'/drupal_chat_cache/'. chatroom_chat_get_cache_file_name($chat_id);
+  $cache_file = file_directory_temp() .'/drupal_chat_cache_' . substr($base_url, 7) . '/' . chatroom_chat_get_cache_file_name($chat_id);
   $cache_timestamp = @filemtime($cache_file);
   $users = chatroom_chat_get_online_list($chat_id, $cache_timestamp);
   $title = '';
@@ -960,8 +961,9 @@
  */
 function chatroom_chat_register_user($chat_id) {
   global $user;
+  global $base_url;
   $session_id = session_id();
-  $cache_file = file_directory_temp() .'/drupal_chat_cache/'. chatroom_chat_get_cache_file_name($chat_id);
+  $cache_file = file_directory_temp() .'/drupal_chat_cache_' . substr($base_url, 7) . '/' . chatroom_chat_get_cache_file_name($chat_id);
   chatroom_chat_update_cache($cache_file);
   $result = db_query("
     SELECT coid
@@ -995,7 +997,7 @@
   global $user, $base_url;
 
   $chatroom_base = drupal_get_path('module', 'chatroom');
-  $cache_file = file_directory_temp() .'/drupal_chat_cache/'. chatroom_chat_get_cache_file_name($chat->ccid);
+  $cache_file = file_directory_temp() .'/drupal_chat_cache_' . substr($base_url, 7) . '/' . chatroom_chat_get_cache_file_name($chat->ccid);
   $cache_timestamp = @filemtime($cache_file);
   $users = chatroom_chat_get_online_list($chat->ccid, $cache_timestamp);
   if (variable_get('configurable_timezones', 1) && $user->uid && strlen($user->timezone)) {
@@ -1519,8 +1521,9 @@
  * common ajax operations to check the cache before loading up Drupal
  */
 function chatroom_chat_get_cache_file_path($chat_id) {
+  global $base_url;
   $cache_file = chatroom_chat_get_cache_file_name($chat_id);
-  $cache_directory = file_directory_temp() .'/drupal_chat_cache';
+  $cache_directory = file_directory_temp() .'/drupal_chat_cache_' . substr($base_url, 7);
   file_check_directory($cache_directory, 1);
   return $cache_directory ."/$cache_file";
 }
@@ -1664,7 +1667,7 @@
   global $base_url;
   $chatroom_base  = drupal_get_path('module', 'chatroom');
   $url  = $base_url .'/'. $chatroom_base .'/chatroomread.php';
-  $cache_directory = file_directory_temp() .'/drupal_chat_cache';
+  $cache_directory = file_directory_temp() .'/drupal_chat_cache_' . substr($base_url, 7);
   file_check_directory($cache_directory, 1);
   return $cache_directory ."/{$type}_". md5($_SERVER['HTTP_HOST'] . $url);
 }