Hi Mike,
Take a look at the stack trace if you have one. There's a lot of very useful info in there normally. "1 for 2" means you're giving something 1 argument when it takes 2. Since you haven't posted the error message, I can't tell what that method is, but I'll take a wild stab that you're calling #complete_task with 1 argument, when it appears to take 2.
Regards, George.
