I can't join any team within the Einstein@home project using BAM.

This doesn't seem to be an error of Einstein@home: I can join a team via their page.

Here's what I do:

*I go to http://boincstats.com/bam/teams.php
*I click "Change/search team" next to "Einstein@home"
*I search for a team (BOINCstats for example)
*I check the "Join"-box and hit "Join"
*I get an error: "No team found"

This also goes for other teams. Subscribing to teams in other projects than Einstein@home does work.

As you requested my BAMid: 44778

This is a problem with Einstein and not BAM.

I'm also still having this problem. 4 projects total on 2 hosts, but I can't join a team for einstein@home using BAM. On the einstein website, I've joined a team successfully, but always get No Team Found on the BAM website....

Einstein had borked their BAM! (actually: AMS) support completely. I have mentioned it to them some months ago.