asterisk users - Jul 2003 - re. rtp.c RTP codec 19

hi ..
when placing a SIP call to a sip host in the states
every few seconds I get an RTP codec 19 error.
I know this is related to comfort noise, and the
call goes through OK ... how can I suppress
the error message ?

Also, many times I get "Invalid CSeq Number"
back from 216.52.153.207 (which is the host
i'm calling) and the call drops.. is there a solution
for this ?

cheers
Dave