As you suspect, there is a system for collecting gasoline vapors and shipping them to the engine. The vapors are stored in a charcoal canister and fed to the engine to burn rather than going to the atmosphere.
There is, however, a whole separate set of codes/sensors for that system so if that was your only problem you'd be very unlikely to get the codes reported.
It is the case, however, that the system does work by vacuum lines - the vapors are fed into the intake that way. Depending on the year (which you didn't mention) you might just be seeing two different problems from the same kind of course - really old, dried up vacuum tubing.
This stuff is really cheap and not hard to replace. There is a vacuum diagram on the underside of your hood. I've known people to just decide to replace all of their vacuum lines once these kinds of problems started to pop up.