Received Errors When Attempting To Preview Certificate in CoursePress

Ugh... I seem to be getting errors from everywhere. This time, as I was attempting to simply Preview the certificate in CoursePress, I received the errors below. Can you help resolve this matter? Thanks in advance.:

Warning: Invalid argument supplied for foreach() in /home/domainna/public_html/ on line 814

Warning: Cannot modify header information - headers already sent by (output started at /home/domainna/public_html/ in /home/domainna/public_html/ on line 7624
TCPDF ERROR: Some data has already been output to browser, can't send PDF file