GK3 error Help!!

I keep making groups and adding slides and I keep getting this error.

Fatal error: Call to undefined function imagecreatetruecolor() in /var/www/sites/netx2/yuisamain/administrator/components/com_gk3_photoslide/classes/class.image.php on line 72


At first i thoght it was a permissions problem but thats not it. Do i have to reinstall.

Hi

Please check if all conditions are available.
Permissions and GD Library support.
You have this option on the PhotoSlide configuration.

Cheers