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!
In your case it's likely to be an issue with bc.i. Contact their support. Create a new separate thread if it turns out not to be an error from their side.