asterisk users - Jun 2008 - iax2_trunk_queue: Maximum trunk data space exceeded

hi folks.

one of the servers i setup recently start exhibiting
"iax2_trunk_queue: Maximum trunk data space exceeded"
errors. there was only 1 call going on at the time.
usually i have to reload chan_iax2.so or restart Asterisk.
but the errors came back within a few minutes. i did a
google search on that error. but nothing useful came up.
i'm kinda stuck. anyone have any ideas?

p.s.
hardware: HP proliant BL460c server
OS: Linux 2.6.18 (Debian Etch AMD64 customize kernel)
Asterisk: 1.4.18
i have several setup with the same version of everything
except the hardware slightly different. they never have
this kind of problems.

-- 
Edwin Lam <edwin.lam at officegeneral.com>
Systems Engineer, Office General, Inc.
Ph: +1 415 439 4988 Fax: +1 415 283 3370
http://pgpkeys.mit.edu:11371/pks/lookup?op=get&search=0xD6506D20