EVALUATION

The code path that is failing is in the WinInstallHandler when the cachedJNLP is null. The reason for this appears to be that the JNLP2Manager initially uses the document base to resolve the JNLP file (http://web-east.east.sun.com/...) and the file is placed in the deployment cache under that key by the DownloadEngine. When the JNLP file is later updated based on the codebase it contains, that cache entry is not updated, and/or a cache entry for the alternate URL (http://j2se.east.sun.com/...) is not created. When the desktop shortcut creation is attempted, the URL for which the cache entry is looked up is the updated one (http://j2se.east.sun.com/...), and since there is no cache entry, the shortcut creation fails. (It isn't clear to me why the shortcuts seem to get partially created.)

The correct fix is probably to update the cache entry while updating the LaunchDesc. Need advice from the Java Web Start team.
                                     

EVALUATION

The failure to create shortcuts occurs when the URL is referenced via

http://web-east.east.sun.com/deployment/www/tests/1.6.0_10/6691243

but not via

http://j2se.east.sun.com/deployment/www/tests/1.6.0_10/6691243

which is how the test case and its codebase are constructed. There is probably something wrong with the determination of the final location of the JNLP file, and the mismatch between this and the codebase of the JNLP file is what is causing the error in Java Web Start's shortcut creation code. The error message should be more descriptive, and in general this case should work, but this is not as high priority as originally thought. Downgrading to P3, but still targeting to 6u11.