Java GSS/JDBC Issue

I have a bit of an unusual issue I'm trying to solve. I develop on a Mac. I'm writing some code that connects to a database using jdbc. I don't have direct access to the db server - to get to it, I have to set up port forwarding on ssh, which goes to a proxy server in the network where the db server resides. The server I proxy into is a Linux server, and the db is MS Sql Server on Windows. Once I've setup the portforwarding, I can connect to the database using a DB browsing tool like SquirrelSQL. When I try to connect to the database using the jdbc code I've written, using the exact same JDBC driver, I get this:

Exception in thread "main" java.sql.SQLException: I/O Error: GSS Failed: Invalid name provided (Mechanism level: Cannot locate default realm)
    at net.sourceforge.jtds.jdbc.TdsCore.login(TdsCore.java:654)
    at net.sourceforge.jtds.jdbc.JtdsConnection.<init>(JtdsConnection.java:371)
    at net.sourceforge.jtds.jdbc.Driver.connect(Driver.java:184)
    at java.sql.DriverManager.getConnection(DriverManager.java:571)
    at java.sql.DriverManager.getConnection(DriverManager.java:233)
    at sql.generator.SQLGenerator.main(SQLGenerator.java:80)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
Caused by: java.io.IOException: GSS Failed: Invalid name provided (Mechanism level: Cannot locate default realm)
    at net.sourceforge.jtds.jdbc.TdsCore.sendMSLoginPkt(TdsCore.java:1976)
    at net.sourceforge.jtds.jdbc.TdsCore.login(TdsCore.java:617)
    ... 10 more

Research on Google indicates that it may be a Kerberos issue, which I haven't had to work with before, but I'm not sure that's right. What is the db browser doing that I need to duplicate in the application?

TIA, Alex

via Chebli Mohamed