how can i remove an ecr lock from my etr?

A search for ETR Machine give results that LOOK to be related to some, non-computer, office quipment.
I found this: ETR Electronic Tax Register.

Among a LOT of other possibilities, I did found this: ECR Electronic Cash Register.

If that's correct, then you posted in the wrong section.
You should post in Office Appliances, Cash Registers

Electro
November 2013