Error 7884 is an invalid network packet, so check out the NICs to insure that

the latest drivers are installed and that "link speed & duplex" are a fixed value (1Gb full duplex?) and autodetect is not specified. Under high network load, autodetect of the optimal link speed does fail and defaults to a low value (100Mb).

See also "How to fine-tune Windows Server 2003 network connections" at

http://articles.techrepublic.com.com/5100-10878_11-5034708.html?tag=rbxccnbtr1