First of all thanks for sharing!
I'm from the adminstration and I have setup a ILIAS 5.1 (beta2) system + chat server, a coworker will be testing the details and contents (I'm not that much "into ilias")..
HTTPS is not implemented in this test system and not activated in the chat server settings..
We have encountered the "not subscribed" error right from the start, when ever we try to use smilies. even typing the word "smilie" prompts the error message..
I created a new chat room on my own and there are no problems at all - now the question is: Can this problem be user rights related? I have administrator role inside Ilias but the information about chat server configuration is almost non-existant...
Any hints?