[Serusers] Load Pa module problem

I am a beginner and just set a SER server, the SER server looks working fine, the SIP-communicator can register it. The SER Version is 08-12-0. But when I tried to load the pa module, there is always a problem: I have set the following modparams in my ser.cfg: loadmodule "/usr/lib/ser/modules/pa.so" ..... modparam("pa", "default_expires", 60) modparam("pa", "pa_domain","rocksteady.cs.fiu.edu") modparam("pa", "use_db", 1) modparam("pa", "db_url", "mysql://ser:heslo@localhost/ser") The ser always failed at modparam("pa", "pa_domain","rocksteady.cs.fiu.edu"). Have I missed something? Could anybody help me how to find document about Pa module? how to load pa module at ser.cfg? I have done a lot search, but the documentation is really hard to find. Thanks a lot Xudong