Dialect class not found: org.hibernate.dialect.ExtendedSQLServerDialect

Question

I'm using a BI suite called Knowage (I hope there are some users here). When i try to build a Meta-Model i get the following error:

Error while initializing Qbe interface java.lang.RuntimeException: Impossible to build model structure

Caused by Dialect class not found: org.hibernate.dialect.ExtendedSQLServerDialect

I really can't find this class anywhere so i'm wondering if someone can help me solving this issue. The only thing i figured out is that maybe i need a .jar file with this class to add in the lib folder of Knowage, but i really can't find anywhere a .jar file containing this class. Thank in advance for the help!