For LVS- there might be missing instance or missing layout. Your netlist and layout are not match. There might be some elements that you forgot to put on your layout.
For DRC- look on what device type it should have been and check the drawing rule if you have put all the necessary layers.
this must be an error in LVS only and not in DRC.
there must be some devices in the schematic that you missed.
check your circuit again or you may refer to the LVS error report; the missing device is indicated there.
check your layer mapping.
it is possible that the layers that you used in layout doesn't correspond to the layers specified in the lvs/drc deck, in that case these layers will be dropped from the layout........and for the deck your gds/layout is empty.
generally the unknown layers( whose gds no. is not defined) are dropped while generating the gdsii with some warning...........
hence you can check your report file for this kind of problem.
sometimes, technology file is detached from your layout library due to some reason.. if that, no layer number is assigned to what you drawn..
i advise you check technology file..