The reason behind this is that IE wont accept 512 Bit Keys. So you have (according to http://joze-senegacnik.blogspot.co.at/2012/11/internet-expoler-can-not-access.html) only one option: Reconfigure the whole thing to use more than 512 bits.
emctl secure dbconsole -key_strength 1024 -reset
This seems to be rather straight forward, but in fact, at my installation it didnt work. A possible reason is that i have not applied the Patch 14503114
So i went with another solution: Use Firefox