I've never seen errors like that on ours.
The company we share the building with had bought one second-hand from another engineer firm we all work with.
I don't know terribly much about the plotter except that it's slow as heck. We only use it when we don't have time to send off to the repro company down the street, or we only need a few sheets.
The only errors I've seen were regarding ink, head alignment, paper alignment, all those basic mechanical things. Never any file problems. :\