With the LBZ you (and we) are at the mercy of Bosch, the entire reprogramming process is handled internally by the ECM, so if it doesn't work then there is little anyone can do. Thankfully, if it fails then your best bet (as you did) is to pull the battery power and try again, the ECM should always be recoverable.
It shouldn't cause a problem on the LBZ, but many users have issues with they hook up aftermarket iPod adaptors, XM Radio adaptors, some of these require connection to the vehicle data bus, unfortunately they also cause major problems when programming. But as i said, this should not be as much of a problem on the LBZ.
You can get a bench harness for the LBZ ECM from
www.speartech.com , but it's probably going to be a bit pricey for the home user to condsider.
Cheers,
Ross