Could not access file: ?? (Opencart 1.5.2.1)

[Anton cona]

Hi

When i send an email showing me this message "Could not access file:/" also in the Error Log those:

2013-05-31 12:06:41 - PHP Warning: Cannot modify header information - headers already sent by (output started at /home4/verdero/public_html/system/library/phpmailer/class.phpmailer.php:1490) in /home4/verdero/public_html/vqmod/vqcache/vq2-system_engine_controller.php on line 28 2013-05-31 12:06:41 - PHP Warning: Cannot modify header information - headers already sent by (output started at /home4/verdero/public_html/system/library/phpmailer/class.phpmailer.php:1490) in /home4/verdero/public_html/vqmod/vqcache/vq2-system_engine_controller.php on line 29

But the Email is going ok.. The problem is Could not access file is showing in a blank page.

can you please help me?