Well, its been quite a while since you made the blacberry wine, but you could of restarted the fermentation with adding more yeast. The yeast could not handle finishing the wine because either, too much sugar and or not enough yeast nutrient. It probably would have been fine if you restarted it. Do you have a 1 gal. winemaking kit?

And about blowing corks, well that happend because fermentation was not done. Did you sweeten it? If you did sweeten it the yeast ate up the sugar and started to referment resulting in a sparkling wine. You can stop this by putting the other bottles in the fridge. But for next time you need to stabilize the wine, add stabilizer or campden tablets.

Well, I am fourteen but I know alot about winemaking cause I have been doing it for 1 1/2 yr, and made over 50 gal. of wine, and I am on another forum which I am quite active in.

English Vintner