Cacti does not display graphics

[lcsmao]

I installed the cacti-0.8.7 on a server slackware 13.1 and am having difficulties with the display of graphics.

When creating the device, identifying cacti normally search the information correctly, but when entering the cacti graphs tab displays the structure correctly but does not display the graphic.

Thanks to all

[BSOD2600]

http://docs.cacti.net/manual:087:4_help ... #debugging