[Asterisk-Users] RTP error problem

[C F]

I get tons of these messages in my logs:
Jan 18 03:59:09 DEBUG[14747]: Didn't get a frame from channel: SIP/204-aada
Jan 18 04:01:34 DEBUG[14747]: Didn't get a frame from channel: SIP/204-6f6f
Jan 18 04:04:26 DEBUG[14747]: Didn't get a frame from channel: SIP/204-d7ed
Jan 18 04:11:05 DEBUG[14747]: Didn't get a frame from channel: SIP/209-3492
Jan 18 04:11:58 DEBUG[14747]: Didn't get a frame from channel: SIP/209-48ad
Jan 18 04:13:01 DEBUG[14747]: Didn't get a frame from channel: SIP/803-7cd6
Jan 18 04:14:55 DEBUG[14747]: Didn't get a frame from channel: SIP/204-4708
Jan 18 04:15:34 DEBUG[14747]: Didn't get a frame from channel: SIP/204-bd3a
Jan 18 04:17:06 DEBUG[14747]: Didn't get a frame from channel: SIP/211-94d7
Jan 18 04:19:07 DEBUG[14747]: Didn't get a frame from channel:
SIP/201-1ee9<ZOMBIE>
Jan 18 04:28:07 DEBUG[14747]: Didn't get a frame from channel: SIP/211-a79f
Jan 18 04:29:13 DEBUG[14747]: Didn't get a frame from channel: SIP/201-bc25
Jan 18 04:31:09 DEBUG[14747]: Didn't get a frame from channel: SIP/209-08df
Jan 18 04:31:17 DEBUG[14747]: Didn't get a frame from channel: SIP/201-85a8
Jan 18 04:34:31 DEBUG[14747]: Didn't get a frame from channel: SIP/204-3726
Jan 18 04:35:30 DEBUG[14747]: Didn't get a frame from channel: SIP/204-e070
Jan 18 04:36:30 DEBUG[14747]: Didn't get a frame from channel: SIP/204-d178
Jan 18 04:38:07 DEBUG[14747]: Didn't get a frame from channel: SIP/204-1bd3
Jan 18 04:39:54 DEBUG[14747]: Didn't get a frame from channel: SIP/201-81d8
Jan 18 04:40:14 DEBUG[14747]: Didn't get a frame from channel: SIP/802-5c6b
Jan 18 04:44:10 DEBUG[14747]: Didn't get a frame from channel: SIP/201-bfbd
Jan 18 04:48:24 DEBUG[14747]: Didn't get a frame from channel: SIP/201-6fbc
Jan 18 04:49:29 DEBUG[14747]: Didn't get a frame from channel: SIP/803-a083
Jan 18 04:50:23 DEBUG[14747]: Didn't get a frame from channel: SIP/201-ee5d
Jan 18 04:54:44 DEBUG[14747]: Didn't get a frame from channel: SIP/201-9849
Jan 18 04:54:50 DEBUG[14747]: Didn't get a frame from channel:
SIP/204-8f05<ZOMBIE>
Jan 18 04:55:56 DEBUG[14747]: Didn't get a frame from channel: SIP/201-6198
Jan 18 04:55:57 DEBUG[14747]: Didn't get a frame from channel: SIP/802-69c8
Jan 18 04:56:33 DEBUG[14747]: Didn't get a frame from channel: SIP/204-dbb2
Jan 18 04:59:15 DEBUG[14747]: Didn't get a frame from channel: SIP/211-3c97
Jan 18 05:01:14 DEBUG[14747]: Didn't get a frame from channel: SIP/201-e190
Jan 18 06:02:49 DEBUG[14747]: Didn't get a frame from channel: SIP/804-30f5

and whenever I do, asterisk stops bridging the call. So here are my questions:
1. Why would I get such an error, or better yet, why would asterisk
not receive a frame?
2. Is that how it should be? that by losing one frame asterisk just
drops the bridge?
3. Am I the only one (I know there are others as in here:
http://lists.digium.com/pipermail/asterisk-users/2006-January/142251.html)
but I want to see if there are even more.

I'm having this on Asterisk 1.2, 1.2.1, 1.0.10, next I'm trying 1.0.9.
I'm using Sipura SPA 3000, and Polycom 500/501s.

Thank You