Just upgraded to beta.14, looks like error may have been introduced prior to rxjs@5.0.0-beta.6. Not sure if this is a rxjs issue.

Error loading jspm_packages/npm/rxjs@5.0.0-beta.6/subject/ReplaySubject.js as "rxjs/subject/ReplaySubject" from jspm_packages/npm/angular2@2.0.0-beta.14/src/http/backends/mock_backend.js