when I was in the test jwt/sign run into a problem, who can help me

[lurui04]

on the RHEL5 find the problem:
[error] 21301#0: *1101 lua entry thread aborted: runtime error: /home/###/###/openresty/lualib/resty/jwt.lua:494: attempt to index a nil value;
but it is ok on my mac;