Verified in 20150520. Uploaded a file, specifying a non-existent file (which repeated the prompt), and uploading the update-cache.txt file attached. No error messages, and the file is uploaded to the LTS.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2015-1168.html