Flash -> php mail, not working on certain servers

[boff]

I have this flash/php mail form that work fine on my hosting server, but not on others. If I run the php by itself or even if I send variables from a html form, it works. The problem seems to be happening inbetween Flash and PHP.

Ideas anyone? :confused:

http://www.busnumber56.com/hwc/mailing_test.swf(does work)
http://www.heavyweightchamp.com.au/tempsite/mailing_test.swf (does not work)

http://www.busnumber56.com/hwc/mailformsource.zip(source files)