It's beyond me why companies think you can't learn their software. This is akin to being unable to learn how to commute to the job, find the cafeteria and learn the names and pecadilloes of co-workers--it takes a little time and training--then any reasonbly intelligent person will become proficient in a few weeks.
When they refuse to hire you because you don't know Quickbooks, what they are essentially saying is the job IS running Quickbooks. Yikes.
As a former teacher, I never got training on whatever the latest fabulous grade-keeping software was, or the training lasted for a 1/2 hour and was a joke. Then, during the first week of school when everything was crazy hectic I'd be attempting to figure out how to enter attendance and grades. It wasn't complicated, but the worst possible time to learn something new. With one day (hell, half a day) of decent training I would've been prepared instead of frazzled.