that is the headers already sent error.
see this portion of the error:
output started at /customers/ashperfectimage.com/ashperfectimage.com/httpd.www/Siteezy_eCart2/UserRegistrationSystem/AdminCP.php:1
it is saying that the output is at line 1 of the AdminCP.php page
See the following page for details on the headers already sent error:
Read through the entire post, your problem is most likely the BOM Unicode Signature bug mentioned at the end.