Is it breaking at the knot during game time or while stringing.
I strung it myself at about 54. and the knots were hard to tie, but didn't really have a problem with it breaking during play time. However i should mention tat i played 4 sessions, about 2 each, and my arm would be dead after i played. So i had to cut them out..
But if they are breaking at the knots, the knots maybe incorrect, or u are pulling them too hard. You should try to keep the knot as small as possible as you are doing the knot, because i found it difficult to get the knot in the gourmet, when i made the knot too big. that might work.