helpo1: Are you sure you are typing it in the correct place? You have to open the stats window (B is the default key AFAIR), then write "marvin" (without the quotation marks, of course) and then close the stats window with, again, B or any other key that you have assigned to it (just be careful not to use any of the letters M A R V I N, for obvious reasons).
Changing the .ini was only necessary in older versions (up to v1.06, IIRC), so you shouldn't need to worry about that.
Thank you for answering. First I open the stats window (levels and skills and such) by pressing B, then I write "marvin", then close the stats window. I thought by now something should've happened but no, nothing happens. I try pressing F2 to open the console, but nothing happens. I wouldn't really need to cheat but I picked up and used those strong herbs from the swamps before I knew they were quest related, and now I'm in trouble. Unless they respawn or something I need to get the console to work so I can get forward. Thank you again for all help.