Well to confirm the logger isn't actually working you could set it to Strict. then you won't be able to chat if it isn't working.
Are you just chatting with yourself? You need to chat with someone else who has this server set as their home server. Sametime will not log chats with yourself.
I'm assuming you performed this step??
By default, Sametime will attempt to store the chat log files in C:\Lotus\Domino\CLData. If you choose to use this default directory, you must create the "CLData" directory manually or the log files will not be generated.
To specify a different directory for storing the chat log files, add the BB_CL_Library_Path= parameter to the [Library] section of the Sametime server's sametime.ini file.
[Library]
BB_CL_LIBRARY_PATH=/<server_data_directory>/<subdirectory_name>
For example, if the Domino server was configured to use "/Notes/Data" for its data directory and you have created a subdirectory called "ChatLogs" for logging Sametime chats, the required entry would be:
[Library]
BB_CL_LIBRARY_PATH=/Notes/Data/ChatLogs
This directory must already exist; it will not be created automatically.
If you're turning on this sample DLL for compliance archiving then I would seriously suggest looking at a tool like Instant IMtegrity which would make your life much easier and would also give you compliance