AARRRGGG! I hate it when yarn "breaks" mid knitting. I hate finding joins in yarn too, but worse is when you are knitting along and the yarn just sort of disintigrates when you tug it. This happens a lot with White Buffalo yarn (the stuff you make Cowichan sweaters from) so I got rid of all I had, it annoyed me too much. I'm finding the Lett-Lopi I'm using does it a little too. It's only lightly spun, not tightly twisted, which is part of the problem. I just had it split about 2 yards past a join I made for the next ball. I ended up ripping back to the join, rather than having joins on two rows in a row. I'm not knitting tightly, or pulling hard on the yarn, it just has weak points. Once knit it is nice and strong fabric, I think I will just have to be careful and deal with it.