loss of power to unattached garage

I have an electrical conundrum and would appreciate any input.
I have an unattached garage that has an electrical line (underground) running to it from the house. I kept having, at first, intermittent circuit breaker trips (I have an older Pushmatic circuit breaker in the main house), even when not using any appliances…and then the problem became constant: every time I would try to reset the breaker, it would immediately trip.
To make a long story short, it turned out to be a partially broken fluorescent bulb in an outdoor light fixture attached to the unattached garage; apparently this was causing a short and thus tripping the breaker.
So after patting myself on the back for finding the problem, I simply replaced the bulb with a standard one and thought that would restore everything to normal. Well it turns out that now the breaker does not trip any longer, but now I have no power to the garage! That didn’t make sense, since I obviously had power just before replacing the bulb since the breaker was tripping!
So, next I presumed that the Pushmatic breaker itself must have failed, and I replaced it. No change. I got out my multimeter and checked for current on the breaker board for that breaker, as well as every other one. All had current and seemed fine.
So, the question is this: did I burn the wiring between the home and garage by forcing trips before replacing the bad bulb? Is there something I am missing as to why the breaker appears to have current but it is not reaching the garage?
Thanks in advance for any insight.