I'm getting Error 80190191 too but only on 1 out of my 3 machines.

2 of them are dedicated CPU miners, the desktop worker is running fine but the server worker refuses to connect with any worker account. I have even deleted and recreated the account on DeepBit as well as created an entirely new worker account and I still get the Error 80190191.

My 3rd machine is a GPU miner but I switched it to my CPU using the same worker account the server is and it connects fine. Doesn't seem to be an account problem since I can use the account on other machines without a problem.