When I ran sslstrip, it ran smoothly. But when it got a request, suddenly I got this error message.

Code:
root@bt:~# sslsniff -a -c facebook.com -s 8888 -w /tmp/log 
sslsniff 0.8 by Moxie Marlinspike running...
terminate called after throwing an instance of 'boost::thread_resource_error'
  what():  boost::thread_resource_error
Aborted
I search through google, and found http://stackoverflow.com/questions/5...-32705-threads

I try to increase my pid_max under /proc/sys/kernel/pid_max from 32768 to 4194303. But I got another error.

Code:
root@bt:~# echo 4194303 > /proc/sys/kernel/pid_max 
bash: echo: write error: Invalid argument
How can I fix this error, so I can run sslsnif without error?