If you're using MS SQL - the 8.5 debugger is a little weird in that it needs a different java driver than vxml server 8.5. Hope this helps!
The following is information one of my students gave me (thanks Keith F!):
For Call Studio 8.5 SQL connections via JDBC to work in production and in debug modes:
The following files/locations are for: sqljdbc_3.0 (can be downloaded from Microsoft)
VXMLServer: C:\Cisco\CVP\VXMLServer\Tomcat\common\lib\sqljdbc4.jar
Studio Debugger: C:\Cisco\CallStudio\eclipse\plugins\com.audiumcorp.studio.runtime_8.5.1\CATALINA_HOME\common\lib\sqljdbc.jar
This solved the issue, I had sqljdbc4.jar and replaced it with sqljdbc.jar and worked now I am getting this...
24.40.50.146.1336510212640.0.TestingDB,05/08/2012 16:50:12.953,A built-in element encountered an exception of type java.lang.UnsatisfiedLinkError. The error was: java.lang.UnsatisfiedLinkError: SNISecGenClientContext
java.lang.UnsatisfiedLinkError: SNISecGenClientContext
at com.microsoft.sqlserver.jdbc.AuthenticationJNI.SNISecGenClientContext(Native Method)
Thanks.