Often when there is a new release, one must solve a little puzzle before being able to play--certain files need to be deleted or whatnot. This time, I could not connect to "Training Server WIP" because it failed to auto-download a 417-byte file. Fortunately, it is not hard to manually download.
The issue can be solved by the following actions:
Go to http://unvanquished.net/downloads/main/
Find the necessary file
Paste it into the 'training' folder
