I had the same happen on my widow the first time I took it out. after looking at the kite to figure out how this happened being it was well in its wind range and it broke in the air, I found that the stand offs were not sewn to the sail right. the the right side had the stand offs attached to the sail about 2-3 inches wider than the left side. took it in to the shop and got an exchange. hasn't happened again and its been in some pretty heavy wind. so maybe check that out. could be the same factory oops.
also make sure your leading edges are both pushed all the way into the nose and are even. make sure spreaders are pushed all the way into the fittings too. they take a little muscle as the fittings are tight.
one other note, my local kite shop is run by the guy who designed the widow maker. he checked out the stand offs on the replacement kite before he let me leave with it and they turned out to be too long and he ground them down to proper spec. could have been another factor in the breaking of the first one. the widows are based on his design but built in china, so they might not have the same attention to detail he does.
go to the sky burner link on the side of the forum and there's a link to his shop. Kites and Fun Things. he may be able to help ya out
hope this helps ya, its my first post