Roespada,

I would start with powering down the server, remove the power cables, hold down the power button for 20 seconds (drains the flea power). After that then open the cover and locate the NVRam_Clr jumper (seen below) and move the jumper over, apply power cables and power up to clear the nvram. After done then power back down and restore jumper to its original location, reinstall the cover, then wait a couple minutes and try powering the server up. 

Let me know if the error persists or is gone.