Post any defects you find in the released or beta versions of the ImageMagick software here. Include the ImageMagick version, OS, and any command-line required to reproduce the problem. Got a patch for a bug? Post it here.
I am using ImageMagick 6.7.2-8 2011-09-23 Q16 on Windows XP.
When rotating images I get torn images (black stripes) for a certain range of angles. I also had a couple of crashes but they seem not to be reproducible.
All your (bad) rotations above 45 degrees work fine for me on IM 6.7.2.8 Q16 Mac OSX Tiger. So it must be a windows specific issue or something odd with your IM install or environment.
We can reproduce the problem you reported. It appears to be threading race condition in the shearing algorithm. We'll provide a fix in the next point release of ImageMagick. Thanks.