iptables-restore: line 42189 failed

I have tried set the script  on about a dozen machines, most work, but on a few I get this error
...
COMMIT
===== /sbin/iptables-restore =====
iptables-restore: line 42189 failed
==================================
Rules update failed: exit code 1 at line 0

This error seems a bit vague, is it known?
The line number varies between machines.
