Last modified: 2012-05-09 01:30:08 UTC
If the request to get an upload token (right after clicking "Upload and continue" on the first page of the wizard) times out or fails otherwise, the following JS error occurs: result is null, mw.Api.js line 142 and the spinner keeps spinning forever.
Merging bugzilla components "Multimedia Usability" and "Upload Wizard"
I believe this is fixed in r84226