Hmmm, I don't see any errors, so I wonder if your corrupt files are simply
incomplete.  The server may be configured to disallow a certain number of
connections.  I would try cutting down the number of concurrent connections
during the run of your mirror to see if the files download.

I tried to have a look at the site, but don't have an account, so couldn't get
past the login page.  I'm assuming that your login/passwd url is set up
correctly, since some of the files download.

You may have problems if the files are accessed by submitting a form.  I don't
know of any mirroring software that can get around that.