When I try and use the 'tag the current build' feature, it fails silently. i.e. the tag isn't created but Hudson doesn't say there was a problem.

I saw that there was a problem with an earlier version of Hudson, so I upgraded to the latest (1.336) but there was no change in the behavior.

I suspect that this is simply because Hudson is accessing the repository anonymously, however, there is no indication that this is the case, either in the GUI or in any log file that I can find.

This brings me to the second problem. The route to setting the subversion credentials in the GUI is extremely well hidden. It has taken me two days of searching the internet to find out how to do it. It is hard to see why it is so difficult to find, surely you could just set this on the main Hudson config page. However that brings up another issue: I haven't set the subversion credentials to see if this is in fact the problem, because this instance of Hudson builds from several subversion URLs that have disjoint sets of users - if I were to set the credentials, some of the builds would break because the authentication/authorization would fail.