I found my MBL doing this yesterday after installing some things. searched all of the web and found no solution. after messing around i found the solution:
symptom: input password to GUI page on browser (any browser) page would not open admin interface only stays on password page without giving invalid password response.
" Leaving the admin password blank results in “invalid password”. Typing the password I set does not show an invalid password but redirects to a blank page or stays on the same password page. Typing the password I set resulted in a repeated “enter owner password” prompt. It did not tell me that the password was invalid. If I typed the password incorrectly, I would get “invalid password”. If I typed it correctly, I would simply get a repeated enter owner password prompt."
cause: dev/md1 folder is full, most likely from transmission filling it up as the incomplete/complete download folder is wrongly specified
solution: delete everything in dev/md1 and tell the software filling it up to do it somewhere else.
steps: SSH via putty or Winscp to locate folder and delete contents. find culprit program and re specify.