Hi hexxeh,
I would gladly receive more information from you indeed. Can you already confirm that:

• you are using the hackable:1 dse1 release?
• you have a Neo Freerunner phone? (as opposed to Neo 1973)
• your issue only applies to incoming calls?
• the issue is that when receiving calls, there is a popup window saying "Unknown error"?
• you are unable to actually answer the call?

Thanks for registering and reporting this bug!