I have been having an issue trying to transfer my Litecoin from Coinbase to Bitstamp Litecoin deposit. I think I am correctly following all the steps. When I am in the Bitstamp Litecoin deposit page I copy the address, paste it into the Coinbase transfer recipient address, fill in the amounts and hit send. I then get an error message to use a valid litecoin address. I then try using the old non M* LTC Multisig address, fill in all details and the error message this time is that I do not have enough funds. But I do have these funds.
Make sure you taken off enough for the transfer fee when sending the coins. That's a common reason for a 'not enough funds' warning.