In gaming (especially MMORPGs popular in China like World of Warcraft), 副本 means 'instance' or 'dungeon' — a separate copy of a game area. 打副本 (dǎ fùběn) means to run/clear a dungeon.
mistakes
Don't confuse 副本 (fùběn, copy/duplicate) with 复制 (fùzhì, to copy/replicate as an action). 副本 is the resulting copy; 复制 is the act of copying.