No buffer space available?

[Ed]

After surfing for around 10 minutes to an hour, the internet suddenly stops working. When i try to ping our router 
(10.0.0.2), it comes up with:
connect: no buffer space available

I am running Mandrake 10 Community on a P-III 733MHz with 320MB of RAM, if that helps.
The problem is only in Mandrake. In Xandros and windows (yeah, i know) the internet 
works fine.
Thanks,
        Ed
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