error auth/img not found - dx_auth

[eluser]Unknown[/eluser]
hi,

I have installed ci v 1.7.1 and dx_auth v 1.0.6.
I try to test the register function of dx_auth, I got the error as followings:

ERROR - 2009-04-05 23:38:43 --> 404 Page Not Found --> auth/img;

I have no idea about this error.

this also changed my another session varible value to 'img'.

could somebody please give me some hints or any solutions to debug this error?

thanks
peili