Uncaught TypeError: Cannot call method getElementsByTagName

A user is unable to download a attachment. The image(s) of the buttons on the form seem to be 'broken' and when I inspect the element I get the following error: Blocked a frame with origin "http://ourapplication.example.co.za" from accessing a frame with origin "https://system.netsuite.com". The frame requesting access has a protocol of "http", the frame being accessed has a protocol of "https". Protocols must match. Uncaught TypeError: Cannot call method 'getElementsByTagName' of undefined. This seems only to happen with this object and the buttons seem fine and works fine with all other objects I have checked. The objects (and attachments) are created after they are retrieved from the mail server using the pop3.fetchmail java action. Any one have an idea how this could happen?
1 answers

There was a reference to base href="https://system.netsuite.com/" in the original HTML message.I think the sender's outlook is setup to include URLs or something, after stripping out the base href="https://system.netsuite.com/" everything works fine, but is this not a potential security threat?