Warning: file_exists() [function.file-exists]: open_basedir restriction in effect

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This error usually arrise if you upload your prestashop installation from your local computer to your hosting or if you changed your hosting company and they have different servers setting.
Warning: file_exists() [function.file-exists]: open_basedir restriction in effect. File(/home/unyu/public_html/modules//right.gif/right.gif.php) is not within the allowed path(s): (/home/unyu:/usr/lib/php:/usr/local/lib/php:/tmp) in /home/unyu/public_html/classes/Tools.php on line 956 

Found solution proposed by prestashop forum moderator. Basically this problem related with php.ini setup. So, you must make sure that your php setting is using following settings:

extension = php_mysql.dll
extension = php_gd2.dll
allow_url_fopen = On
register_globals = Off
magic_quotes_gpc = Off
allow_url_include = Off