I just turned on write-access commits from the HTTP side. So you should be able to do a checkout with authentication without HTTPS. Of course the password will be sent in the clear. The theory is that removing the HTTPS will work around the bug in HTTPS+WebDav. And of course relieve some CPU stress on the server. I was able to flawlessly do a trunk checkout, and a simple commit.
HTH.
PS. Since the password is in the clear.. Please consider your choice of passwords carefully.
Indeed, I just tried to change my password, but couldn't actually figure out how.... so I go to svn.boost.org select the "change your Subversion password" option, and that takes me to the full svnmanager page with options for everything it seems *except* resetting my password. This could just be because I have admin privileges that it's not intuitive? BTW I tried User Admin -> Edit User -> Select but that just leads to an empty page? Cheers, John.