Ping No Buffer Space Available

i have a custom setup, front end, that serves the apache requests, and a remote SQL Server.

the SQL traffic runs on the internal network.

the front end runs freebsd 6.2, and apache 2.2 with php 5.2.5

the sql server runs centos 5.1, and mysql 5.0.45

tonight, i found that my website was not working, i logged in, and i saw that when i tried to ping the internal network, i had that error:

ping No buffer space available

i was trying to ping the sql server, from the front end. the sql server worked fine, i could ping other servers in the internal network, but the front end's internal card allowed no traffic.

I tried restarting the internal network card, state up/down, did not solve the issue.