Here's how I resolved the "Fatal error: Call to undefined function: imagecreate()" error using Gentoo:
1) add a USE flag for gdb in /etc/make.conf
USE="3dnow avi [whatever else you have] gdb"
Note: here's a list of all of the USE flags:
http://www.gentoo.org/dyn/use-index.xml
2) unmerged mod_php
*Note* It could take awhile to "remerge" as it may need to compile several dependancies...do this during not production hours and have a backup if you absolutely cannot have downtime
emerge -C mod_php
3) emerged mod_php
emerge -p mod_php
# find out if it's going to take awhile
4) edit /etc/php/apach2-php4/php.ini
uncomment the "extension=php_gd2.dll" line
5) Restart apache2
/etc/init.d/apache2 restart
Hope this helps!
--
Cooper Stevenson
GenCom
http://www.gencom.us