I have most of my debian boxes using lvm2. On one (sadly my main server I was getting):
Incorrect metadata area header checksum
but everything seemed to be working.
So - I ran vgscan. This stated that there was a problem on /dev/hdd. Well - /dev/hdd is a cdrom unit - so no lvm there.
I edited /etc/lvm/lvm.conf and changed
filter = [ "r|/dev/cdrom|" ]
filter = [ "r|/dev/cdrom|", "r|/dev/hdd|" ]
which solves the issue for me.