Hi FilipeSizilio
Error Code 2900:0221
Msg: IPMI - Jul 13 16:05:47 2013: system board:: Voltage sensor (1.05V PG) state asserted "System Board".
I would say the voltage regulator on the mainboard is faulty and is has to be replaced.
What you can try is to start the server without PCIe cards in it and just a single DIMM on the first slot.
In this way you can rule out if there are any other components causing the issue.
Cheers.