Java Security

I'm having some problems getting JAAS (specifically, the Kerberos module) to retrieve kerberos tickets out of the local cache. When the Kerberos module attempts to contact the cache, it makes a call to the Credentials object, calling the acquireTGTFromCache function. This object is in the sun.security.krb5 package, whose source is not available. Somewhere in this acquireTGTFromCache function, a series of Win32 calls are made to attempt to retrieve the ticket, including (for some reason) a call to the DsGetDcName function (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/netdir/ad/dsgetdcname.asp), which returns the name of the domain controller for a specific domain. I'm not exactly sure why this call is made, since I don't understand why knowledge of the DC is needed to access the local ticket cache. In any case, that DcGetDcName function is returning error 1355: ERROR_NO_SUCH_DOMAIN.

This error does not occur when I do not use the ticket cache and enter the username and password manually - the test application successfully authenticates against the AD server without any domain errors, so this doesn't appear to be a configuration issue with the AD server. I've verified this error on a couple of different machines as well. I've tried to find a problem with my test application, but it appears to be pretty much identical to the test application in Sun's JAAS tutorial.

Any help anyone could provide would be most appreciated - thanks!