Problem updating linux (kernel) in GUTSY

[David A. Cobb]

As part of updating to 'gutsy', I installed grub-pc (that's grup v2, I 
guess).  Now I cannot complete installing any update to linux-x.y.z 
packages; all fail with 'grub-probe: Unknown filesystem'

My boot partition is ext2, my linux root is ReiserFS.  Rather obviously, 
both are well-known or I would be unable to boot at all.

Advice requested, TIA.