It looks like the Microsoft JDBC drivers are not found by your Denodo deployment. Have you provided Denodo with the Microsoft JDBC drivers?
Microsoft JDBC drivers are not included by default (Virtual DataPort Administration Guide, Appendix 16.1). To add them, you typically need to download Microsoft JDBC drivers from the Microsoft Download Center (http://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=11774) and extract the jar file containing the JDBC driver into the <DENODO_HOME>\extensions\thirdparty\lib folder.
Hope it helps