[Click] FromHost initialize failed

[weirong sun]

hi,i am running same click router script in several computers,and only one
machine failed,the following is the error:
While initializing ‘frd1 :: FromHost’:
  fake1: `/sbin/ifconfig fake1 192.168.1.2 netmask 255.255.255.0 up
2>/dev/null' failed
  (Perhaps Ethertap is in a kernel module that you haven't loaded yet?)
Router could not be initialized!
this computer's os is fedora,can anyone tell me what should i do to solve
this problem? thanks!