NEC errors in the 300 range generally pertain to an issue with the ICP board.  The ICP board contains the projector's security certificate so this can be a fatal one.  There are two batteries on the ICP board.  One battery can be changed, the other cannot.  When the non-changeable battery dies the board loses its security certificate and must be replaced.

Try the following procedures

1,      Reseat the ICP board

2.      Try to push the ICP f/w and data into the unit using the DCC software

3.      Replace the ICP board