I'm having the same problem - "Previous Tx is unspendable"
From 1Jig98ukzPTxzGU9bGTfxB9fqwe3rKcDtb which is my Blockchain wallet address for receiving newly mined coins from Eligius.
Sending to 1DrZjFeT6ajM4WBEfTgDobtm1Ee7hy8sfP
Any help appreciated!
Are you waiting for "block maturity" ?
If at least one of your inputs doesn't have 100+ confirmations you can't spend it.