Form works for me (acct owner) but not for user

One of my VH-hosted sites is powerretailing.com, which (to me) seems to be working fine today. I have a partner who handles the emails that come from the contact form on that URL; to test that form he tried filling it out this morning, and when he clicked “Submit” he got the following error message (and NOT the Thank You page that should come up): Warning: file_get_contents(./error.html) [function.file-get-contents]: failed to open stream: No such file or directory in /home/vtrsgwu/public_html/powerretailing/index.php on line 33 He also says he’s not receiving any form data at his email address, which is in Form Properties. Based on what I see on line 33 of the page’s code, $errorcode = file_get_contents($error_url, I created an error page and put its URL into Form Properties

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Form works for me (acct owner) but not for user