TE120P Got reject for frame & retransmitting frame

Hi , I can see in my logs this error:

[Oct 3 14:45:40] ERROR[3848] chan_zap.c: !! Got reject for frame 127, retransmitting frame 1 now, updating n_r!
[Oct 3 14:48:00] ERROR[3848] chan_zap.c: !! Got reject for frame 8, retransmitting frame 8 now, updating n_r!
[Oct 3 14:48:00] ERROR[3848] chan_zap.c: !! Got reject for frame 8, retransmitting frame 9 now, updating n_r!
[Oct 3 14:55:12] ERROR[3848] chan_zap.c: !! Got reject for frame 51, retransmitting frame 51 now, updating n_r!
[Oct 3 14:55:12] ERROR[3848] chan_zap.c: !! Got reject for frame 51, retransmitting frame 52 now, updating n_r!
[Oct 3 15:06:25] ERROR[3848] chan_zap.c: !! Got reject for frame 84, retransmitting frame 84 now, updating n_r!
[Oct 3 15:06:25] ERROR[3848] chan_zap.c: !! Got reject for frame 84, retransmitting frame 85 now, updating n_r!
[Oct 3 15:06:25] ERROR[3848] chan_zap.c: !! Got reject for frame 84, retransmitting frame 86 now, updating n_r!
[Oct 3 16:46:18] ERROR[3848] chan_zap.c: !! Got reject for frame 77, retransmitting frame 77 now, updating n_r!
[Oct 3 16:46:18] ERROR[3848] chan_zap.c: !! Got reject for frame 77, retransmitting frame 78 now, updating n_r!

Not all Errors implicate a drop call, i hve a few drops , and i read tahat this is due a IRQ missess and depends on the system load and echo cancellation, but od dont know what i must do.
i have installed asterisk 1.4.20, librpi 1.4.4 zaptel 1.4.9&addond 1.4.7

Upgrade Zaptel! The latest release 1.4.12.1 will do.

I did it , but still have the same problems:

[Oct 7 08:51:44] ERROR[18910] chan_dahdi.c: !! Got reject for frame 42, retransmitting frame 42 now, updating n_r!
[Oct 7 08:51:44] ERROR[18910] chan_dahdi.c: !! Got reject for frame 42, retransmitting frame 43 now, updating n_r!
[Oct 7 08:51:44] ERROR[18910] chan_dahdi.c: !! Got reject for frame 42, retransmitting frame 44 now, updating n_r!

i found this :
bugs.digium.com/view.php?id=11189

“After lots of investigation, it has been determined that the rejected frames (or retransmissions for SS7) are caused by IRQ misses occurring in DAHDI and depends on the system load and echo cancellation. This behavior is expected so I’m closing this bug as the other described issues were already fixed.”

So this bug was already close?? in wgat version??

Please contact Digium support.

support@digium.com
+1 256 428 6161