Hi
Thanks for the response. I've narrowed it down an issue when InfoPath is submitting a form using "Rules and Custom Code".
For some reason when using the standard "Submit" method for InfoPath, it will check if the form is valid first and then run the rules and then submit the form.
However, when using "Rules and Custom Code" it will run the rules on the submit button first and then check if the form is valid and then submit or not submit. The problem for me here is, when the submit button is clicked I change the status of a variable called wf_status. My submission of a form is dependent on this variable so if my form is invalid, the variable gets changed and when the form is once valid again it won't submit because the variable doesn't meet my condition for submission.
I'm going to try and resolve this using rules otherwise I will write code for the submit method in the event.
Thanks for all the help guys :)