generate pdf link is disabled

my generate pdf link is disabled. how can I enable it ?

http://la-lu.com/thumb/uploads/pictures/8/a64f4222-648c-4f6c-b096-3c7a8b5694cb.png

here is my splunk version 5.0.2, build 149561 here is my OS info SunOS trafalgar 5.10 Generic_147441-01 i86pc i386 i86pc

thanks in advance