Hmmmm I might be wrong here (probably am to be honest) but I was under the impression that pcre.backtrack_limit would be in php.ini?
I couldn't find it in my php.ini so double checked via google that that is where it should be and according to
http://www.phpro.org/manual/ref.pcre.html I assumed correctly.
I added "pcre.backtrack_limit 1000000" to php.ini and restarted apache but when checking phpinfo() via the XAMPP control panel pcre.backtrack_limit was still showing as 100,000.
Am I missing something obvious here or am I looking in the wrong place?