If You are insatlling the 1.x branch then make sure the PHP version
 used is at least 4.3.x (preferable 4.3.10 or higher) and that the PHP
 version have compiled support for GD library. It is absolutely critical
 that GD is fully working. Please see the earlier sections on how to
 make sure. JpGraph supports both GD 1.x and GD 2.x However it is
 strongly recommended to use GD 2.x since that will improve performance
 and support true color images as well as alphablending.
 If You are insatlling the 2.x branch then make sure the PHP version
 used is at least 5.0.1 (preferable 5.0.5 or higher) and that the PHP
 version have compiled support for GD 2.x library. Please note that the
 2.x branch will not work with PHP 4.x