When you try to install new modules onto a Drupal setup hosted on a Blacknight.ie Unix hosting plan do you get errors like the following about the installed PHP version?

"This module requires PHP version 5.2.* and is incompatible with PHP version 4.4.7."

If so don't panic, your hosting paln will almost certainly have PHP 5.2 installed and configured, all you have to do is to go to the control panel and disable PHP 4.x support, this will then allow PHP 5.2.x to shine through and should keep your modules from complaining!

So, log into your control panel and navigate to the 'Web Space/Web Site Configuration' page and then make sure that 'PHP Support' is set to 'off' and that 'PHP5 Support' is set to 'on' - and that should fix things...