I currently received a file from our architects containing linetypes. I need to edit these linetypes but cannot find the .lin file attached to the drawing. Is there anyway I can edit these line types (hidden .lin file or something)? They come in fine, which makes me believe they must be attached to the drawing someway, which means there should be a .lin file somewhere. I'd appreciate the help.

You can use our LinOut utility to extract a LIN file from a DWG drawing. See:
http://www.cadforum.cz/cadforum_en/qaID.asp?tip=3958