(thanks for the forward Zid)
Send a lspci -vvx but I guess that it is all 'ff' when the problem happens.
Either it is reliably fixed with patches #0001 ... #0006 at
http://userweb.kernel.org/~romieu/r8169/2.6.27-rc3/20080818/
or something broke in the PCI configuration space.
--
Ueimor
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