I've also experienced this problem for the last 24hrs. Can't upload data either directly (or indirectly via FTP clients).
I can load data fine to a local instance of Galaxy at my university. So it must be a specific problem to the main server?
There are some issues with Galaxy Main at http://usegalaxy.org. This may have impacted jobs as of late Weds and now is manifesting as temporary downtime (two distinct issues). Please follow here for details and updates: https://biostar.usegalaxy.org/p/20698/
Our apologies for the inconvenience, Jen, Galaxy team