Please do not ignore the notice that clearly states PHP 5.2 is not suitable for Easy CSV Importer. We are finding a lot of users ignore the notice and proceed to use the plugin.
PHP 5.3 is more reliable and 5.5 has been released with many fixes. WordPress itself has functions for 5.3 which operate better than their depreciated versions for PHP 5.2 so its not all about this plugin.
Right now there are few reasons not to use 5.3 with a new WordPress installation or a WP 3.6 update but if you do have a reason you must not use our plugin.
You may switch PHP versions using hosting control panel. Look for an icon named something like "Configure PHP" or "PHP Config" or "PHP Setup" etc.