Just spent the last hour trying to figure out why a simple php form was breaking WordPress. The answer was a variable name clash. I used a variable called ‘name’ in my form which seems to be linked the WP tag tags (!).

To get things working I renamed ‘name’ to ‘signUpName’.

Whilst scrabbling around for answers I did come across a good article about a security vulnerability when using the PHP_Self command, it’s well worth a read before you build your next form.