asterisk users - Oct 2004 - starting problem

Good day all
I download the lates and one back version of asterisk and I get the 
following error!

Asterisk Dynamic Loader Starting:
  == Parsing '/etc/asterisk/modules.conf': Found
 [chan_modem.so]Oct  7 14:55:02 WARNING[-1084874080]: loader.c:248 
ast_load_resource: /usr/lib/asterisk/modules/chan_modem.so: undefined 
symbol: __use_ast_pthread_create_instead__
Oct  7 14:55:02 WARNING[-1084874080]: loader.c:380 load_modules: Loading 
module chan_modem.so failed!


Please help