[syslog-ng] keep_hostname (yes); and source file

Hello, I have a file, /srv/http/foo/var/log/system.log that I would like sent to our central log. This config was not working: @version: 3.0 # # /etc/syslog-ng.conf # options { stats_freq (0); flush_lines (0); time_reopen (10); log_fifo_size (1000); long_hostnames(off); use_dns (no); use_fqdn (no); create_dirs (no); keep_hostname (yes); perm(0640); group("log"); }; source s_foo { file("/srv/http/foo/var/log/system.log"); }; log { source(s_foo); destination(d_net); }; destination d_net { udp("host.org"); }; It does work if I comment out 'keep_hostname (yes);'. Can someone explain to me why this is? -steve