Transactions are given a number, called the nonce. The rule is that an account may only have transactions happen in order of the nonce.
On the ETC chain, what's likely happened is that the too-high transaction has nonce X, and no transaction afterwards (nonce X+1, X+2...) will happen, due to the unprocessable earlier transaction.
All you need to do is, one way or another, provide a valid transaction to the ETC network with the right nonce, and things will start sorting themselves out.
There's a simple possible fix: sync a GUI wallet to the ETC chain, and then send a small transaction. If the wallet doesn't know of the bad transaction, it'll automatically pick the next available nonce to use, which will overwrite that bad transaction. Hopefully things will unclog after that, and you can also use that ETC-synced wallet to finish the job.
You can definitely do this in the console, using eth.sendTransaction(). It's more technically complicated, so I would strongly recommend at least trying the GUI solution first.
EDIT: If this works, what'll likely happen next is that the subsequent transactions you sent (the ones that didn't occur on the ETC chain) will happen. The ETC will therefore be partially split (since you overwrote that large splitting transaction with a smaller, working one). Much of it will still be at the original address.
Chances are that you can finish the job simply by sending normal transactions to your desired address, since the imbalance of ETC on the original address will prevent it from being replayed. As I mentioned, as long as you have control of every address involved, on any chain, you can sort it out eventually.
If you wish, you can post a link to your addresses (on etherscan.io or a similar site) and I may be able to give more specific advice.
