Warning: require(./Lib/ThinkPHP/ThinkPHP.php) [function.require]: failed to open stream: No such file or directory in C:\wwwroot\playmuzica.com\index.php on line 15

Fatal error: require() [function.require]: Failed opening required './Lib/ThinkPHP/ThinkPHP.php' (include_path='.;C:\php5\pear') in C:\wwwroot\playmuzica.com\index.php on line 15