Don't know if the problem still exists.
For me it does, better it did..
i don't think it's a problem with the kernel (maybe as well, but i use a custom 18.104.22.168
kernel), it is a problem with the versions of lvm2 and libdevmapper. i use debian sarge stable where the versions of lvm is
2.01.04-5 and of libdevmapper 1.01.00-4.. but if you want to get it working you need the 2.02 and 1.02.
So i upgraded the lvm and libdevmapper packages to these versions and the removal of the snapshots work without problems.