I used the coinb.in UI to sign the transaction with the private key from
dumpprivkey 18UfvFPqRp5LXwhQTZnkUy5bZxyqrbujTm.
I manually constructed the nonsense output and lock time, so maybe that messed things up? Or coinb.in doesn't know how to sign it?
I didn't try using qt because I haven't been synchronized since the April bubble. I'm probably no further than block 230000
Coinb.in does know how to sign the TX. Did you try again?
If you can't use Bitcoin core, why don't you try lightwallets like Electrum and Multibit?
~~MZ~~