to me its your server error... what web server do you have? apache?..
contact your host for changing max time on execution variable... because i have reloaded 2-3 times your forum, and it not stop on the same place on loading... so it seems you don't have any script problem..
here is info:
Code:
http://www.cyberciti.biz/faq/wordpress-to-wordpress-php-import-tweak/