I don't think I've actually ever tried setting the withdrawal limit on an address to 0 and I'm not sure if it can be undone, I'll have to ask catia about it. One thing to keep in mind is that when you increase the withdrawal limit it will take 100 blocks before the withdrawal limit gets updated. But I'm not sure why it's saying you have insufficient funds, I'm guessing it has something to do with your withdrawal limit being 0. The setlimit transactions are pretty weird, the input and output address are the same, where the output value is the new limit value and the difference between the input and output values is the fee. But I think if you use a command like gettransaction it wont show the true structure of the tx, it will show a simplified version of the transaction which makes more sense.