The problem will occur if system cache is configured, and you try to uninstall a jnlp application that is uninstalled already.

e.g javaws -wait -system -uninstall <jnlp url>

it will corrupt the windows add/remove program, and you can no longer uninstall other applications.

it's a java web start bug in 5u11. I tried with 6u1 and problem does not exists.