upgrade permits unusable options and then errors

I got this:

Using saved location: http://people.samba.org/bzr/jelmer/bzr-rebase/trunk/
bzr: ERROR: Tags not supported by BzrBranch5('file:///home/jw2328/.bazaar/plugins/rebase/'); you may be able to use bzr upgrade --dirstate-tags.

So I did this:

jw2328@twitch:plugins/rebase:1031:0% bzr upgrade --dirstate-tags
starting upgrade of file:///home/jw2328/.bazaar/plugins/rebase/
making backup of tree history
file:///home/jw2328/.bazaar/plugins/rebase/.bzr has been backed up to file:///home/jw2328/.bazaar/plugins/rebase/.bzr.backup
if conversion fails, you can move this directory back to .bzr
if it succeeds, you can remove this directory if you wish
starting repository conversion
bzr: ERROR: Cannot convert to format <RepositoryFormatKnit1>. Does not support rich root data.

So I did what I was told, but now I'm told that I can't, and there is no hint as to what might solve the issue.

Also this repository (not shared, in the branch's .bzr), can only be a few weeks old as it is bzr-rebase, so why
can't I upgrade from a recent format?

Thanks,

James