Even though WordPress still officially supports it, with version 1.0 of WP Tiles we have finally dropped support for PHP 5.2. PHP 5.3 was released in 2009 – that is 6 years ago by now! That is the same year as Internet Explorer 8. In that light, supporting PHP 5.2 it a bit like supporting IE7. Ouch.
PHP 5.3 comes with new language features that makes development of the plugin quicker and more fun, making it a better plugin for the majority that is on PHP 5.3+.
If you are really stuck on PHP 5.2 and still want to use WP Tiles, you can still use version 0.6.1. But make sure you are really stuck first!
Most shared hosting companies offer PHP 5.3+ support now, but may not have automatically enabled it on every account. Here are guides to upgrading your PHP version on some of the most popular hosting companies for WordPress sites:
HostGator and GoDaddy: check out this blog.
Bluehost: look here.