Last modified: 2009-07-31 10:16:09 UTC
r53416 changed the sourcetype from Url to web, UploadBase::createFromRequest uses this to determine which class to load
$className = 'UploadFrom' . $type;
There is no UploadFromweb class so null is returned to SpecialUpload so it spits you back to the upload form with no errors and no clue why it failed.
Fixed in r54076.