Earlier I noticed that the Jenkins Build for Pier3 Addons weren't being built - after sending an email to the the Pier mailing list, Stephan Eggermont re-enabled it. The problem was the Pharo 5 3.0 build was broken, as is the Pharo 3 Pier 3.1 build (Pharo 4 was fine for both).
Tried to load the stable Pier3 into the Pier3.1 running on Pharo 5 using:
Gofer new
url: 'http://smalltalkhub.com/mc/Pier/Pier3/main';
package: 'ConfigurationOfPier3';
load.It failed with stream error: UTF8InvalidText(Object)>>subclassResponsibility while loading Pier-Seaside-NickAger.539.mcz (I had expected it to fail loading a reference to TimeStamp). When selecting the above package from Monticello, it raises the same error. Changed ConfigurationOfPier3>>version301: to list Pier-Seaside-JohnCBorden.557, it still failed with the same error, next updated version300: and it was successful (with a warning about using subString:).