It is not properly installed. If you have done, your phpinfo should show


GD Support enabled
GD Version bundled (2.0.28 compatible)
FreeType Support enabled
FreeType Linkage with freetype
FreeType Version 2.1.9
GIF Read Support enabled
GIF Create Support enabled
JPG Support enabled
PNG Support enabled
WBMP Support enabled
XPM Support enabled
XBM Support enabled
See the phpinfo at

http://video.bizhat.com/phpinfo.php