I've been trying to update my Zenworks 11.0 server to Zenworks 11 SP2, but am unable to.

I've downloaded the ISO file 5 times already and checked the MD5 hash, I even tried a downloadmanager.

The problem I'm experiencing is that the setup starts, but then hangs at the License Agreement. The Next and Cancel button are grayed out.
I've left it an entire day, but it doesn't continue.

What could this be?