The following message is displayed when you have exceeded the number of SQL Server licenses that you have registered:

An error was detected whilst accessing the Vault Database 
'name': [Microsoft][ODBC SQL Server Driver][SQL Server]Login 
failed- The maximum simultaneous user count of n licenses 
for this server has been exceeded. Additional licenses 
should be obtained and registered using the Licensing 
application in the NT Control Panel.

If you are running SQL Enterprise Manager remotely, you require an extra SQL Server license.

Enterprise Vault creates and accesses the Vault Directory Database and the vault store databases. The number of licenses depends on your licensing type. For example, if you are using per-server licensing, and both databases are located on the same computer, you require one Client Access License. If the two databases are on different computers, you require two Client Access Licenses.