krjt One possibility is that your website hosting service just updated the version of PHP running on your web server. Which version of Machform are you using? If it's not the latest version of Machform, updating it might help, but it depends on the version of PHP running on your web server. You should be able to contact your hosting service to find out the PHP version number.
Of course, this possibility may not apply to you; it is hard to give a better answer without more details. Your best bet might be to submit a help ticket to Machform support, if your support contract is current.