"Should I set register_globals to ON in PHP?" saith the newbie.

"Should I set register_globals to ON in PHP?" I would like to install a weblog for my website. I found this weblog: http://somery.danwa.net/ I would like to install it but it requires register_globals to be set to ON. Currently register_globals is set to OFF. I don't know the significance of this - can someone advise if this is a bad idea / security problem? If not a problem where do I set the register_globals to ON? How do I do that. Thanks in advance. Dan