Whenever a machine fails there's a risk of lost votes. More importantly these machines are just insecure. We need voting machines with open source hardware, open source software, and encrypted, hashed, anonymous publicly available vote records. Ask for a password. Hash the password, the vote, the polling booth's number, and the time (in 15 minute increments) and make that immediately publicly available.
Each voter can then go to a publicly accessible website and enter where and when he voted and what password he used, and be told how he voted. If that bothers you add a unique password inside each booth the person can alternatively use to be told he voted differently, or allow entry of an alternate password to be answered a user-selectable vote.
The hashed verifiable votes will be proof against election fraud.