ping: sendto: No buffer space available

[Baldur Gislason]

I have a script in my crontab that runs ping to check the state of the 
internet connection. The internet connection is PPTP using kernel ppp.
When there's much load on the connection I get an occasional error mail 
from crontab saying

ping: sendto: No buffer space available

I have tried increasing kern.ipc.nmbclusters but that makes no difference. What can I do to get rid of this, other than ignore stderr from ping?

Baldur