Hmm, I tried it on two other servers.
The first one also ran PHP in CGI mode and I got the same thing "500 Internal Server Error", although the server didn't report similar errors, log/calem.log did :
2007-10-11 13:52:09,988 DEBUG main - sid=; aid=, Post data:
2007-10-11 13:52:09,988 INFO main - Received request to launch: client/launchpad/CalemLoginLite.php, aid=
Which is obviously missing the sid and aid data.
(FYI - You can tell PHP is running in CGI mode because phpinfo.php reports "Server API CGI")
The second server runs PHP as an apache module but all it produced was a blank screen. Even stranger, there were no errors in the server's logs or in calem.log. I knew something was wrong when running "PHP createSchema.php" from the command line did nothing (I ended up copying the DB over from another test installation)
All three servers I tried are running LAMP, php5, have PDO, all the chart includes and 755 as the permissions of all the files.
I think the author needs to take CalemEAM and make sure it works on a variety of linux production servers before it will get wide spread use.