I've tryed to install pier from your squeakmap repository. First I take a fresh Seaside-image from Seaside-website and after this a load the packages Margrit and Pier with monticello. After restart the image I tryed to start Seaside-pier in the webbrowswer. There an error comes up with a message not understood of an class from Seaside. So I think it is an version-problem with seaside. What package versiion (mcz) you use for the actual version of pier?