Can you attach the backtrace of the kernel panic (you'll probably find it in /var/log/syslog) to this bug, please?
** Changed in: Ubuntu
Sourcepackagename: None => linux-source-2.6.15
** Changed in: linux-source-2.6.15 (Ubuntu)
Status: Unconfirmed => Needs Info
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nfs + vlan = kernel panic
https://launchpad.net/malone/bugs/37680