iptables error: resource temporarily unavailable

[Eric Jarman <ehj38230@xxxxxxxxxxxxxx>]

I have a firewall machine set up, with a fairly large number of rules in 
the mangle table (>4000) set up as an authenticated gateway.  Routinely, 
I am getting this error when trying to add new rules to the mangle table:

iptables: Resource temporarily unavailable.

Are there any tuning parameters that I can set to try to avoid this problem?