I believe this is some kind of hardware issue related to USB.
Here is a thread about the same issue, just on a different ASROck board, but same error codehttp://forums.tweaktown.com/asrock/44426-p67-extreme-4-code-b4.html?daysprune=-1#post394794
Here's a solution one person said worked for him.http://www.asrock.com/mb/beta.asp?Model=Z68%20Extreme3%20Gen3
Read the "How To Update" for L1.23, save file to USB drive, follow instructions to flash bios. GOOD LUCK