jQuery Forum

I recently attempted to ajaxify the file upload process, admittedly not using the ajaxForm plugin, some research there is a security restriction preventing javascript access to the file upload functionality. It is to protect the user from revealing their directory structure to malicious code. 

This could be the reason for an error code occurring, although as previously mentioned I have no direct experience with this plugin.

I ended up settling on the hidden iframe solution. Where the form is set to target an iframe that upon successful processing returns a value to the parent page. 

Detailed here.