That’s a XAMPP issue with php timeout; ask in the XAMPP forums on how to change it in your php.ini
http://www.apachefriends.org/f/viewforum.php?f=34
Faced similar situation while importing a long script with so many external links. It can happen when a plugin/theme is using a function ‘wp_get_http’ which explicitly defines timeout limit to 60 seconds, so even if we add a line set_time_limit(0) or write it in php.ini, it won’t matter as the function changes that right before calling the actual function to fetch the file. As far as I’ve seen it can’t even be overridden by any action or filter, so had to change it manually in functions.php before starting the script.