[exim] non-zero status 0x000b: terminated by signal 11

Hi,

We are getting this error when sending mail to a certain ISP.

----------------------------------------------------------------
R=dnslookup T=remote_smtp defer (-1): smtp transport process \
returned non-zero status 0x000b: terminated by signal 11
----------------------------------------------------------------

Then the messages becomes Frozen. I searched google and the
Exim spec for clues and came up with nothing.
I feel confident it is a problem on the other end but I need
to know what that error means before I contact the ISP.

What does that error mean exactly?