LOL... it says right there: "64 tx-size"
You are attempting to create a transaction that is 173,354 bytes!!
That's around 760x the size of a "standard" transaction (226 bytes)!
I think the limit is something like 100,000 bytes (but don't quote me on that). I suggest you maybe cut down on the number of inputs you're using to send this transaction.
Trying using the "Coins" tab ("View -> Show Coins") and selecting a couple of hundred inputs at a time and breaking your transaction up into say 10 different transactions.