[Toehead]

Perhaps he means one jug is seized. If it's seized from sitting, it might be worth investigating. Sometimes they can be freed (MMO/ATF down the jug, slowly rock the crank back and forth ). If it's seized from lack of oil (was there oil in it when you got it? ) or has a thrown rod (does it turn easily until it suddenly locks, or do you feel/hear something rattling around in the case when you turn the crank? ) then that is a different story.

Like MTB says, try to physically turn the engine and see if you can get any movement.

 

[Toehead]

I don't want to discourage you from seeking a professional, but you can tell if the engine is seized really easily. Try to rotate it by hand, through at least one full revolution, and report back. Usually this can be done by just spinning the fan cover.