Internal pools uses DataDirect driver, the connection URL must be something like:
Associated Driver Alias: DataDirect Connect JDBC SQL Server Driver
Database URL: jdbc:wm:sqlserver://localhost:1433;databaseName=myDatabase
From the error you have, looks like you have configured a native SQL server driver.
Check your connection URL and Driver alias.
#webMethods#Adapters-and-E-Standards#Integration-Server-and-ESB