Basic question on rlm_perl

hi, I am building freeradius 2.1.3 on ubuntu (configure/make/make install) I am trying to use perl module, but when I can't start my server. I have put "perl" as a module in my radiusd.conf file. I don't file the rlm_perl*.so file in /usr/local/lib/ where all the other rlm_*.so files are located. What am I missing? I also tried to configure with the experimental modules flag. Thanks -a