I would also recommend checking for the following in your sametime.ini
[Config]
VPS_ALLOWED_LOGIN_TYPES=
Make sure you have all client types needed defined, such as
101A and 1001
Lotus Software Knowledge Base Document
Title: How to determine the Client Type that is connecting to a Sametime server
Doc #: 1114318
URL:
http://www.ibm.com/support/docview.wss?rs=899&uid=swg21114318