I've been occasionally seeing the error message:
CGAffineTransformInvert: singular matrix
In the logging area of Xcode. This seems to occur (infrequently, fortunately) when I pinch to resize a web site within a UIWebView. [Commercial website, not my own.] Since I do no Affine Transformations in my App, I'm wondering if this might be a bug/feature of UIWebView. If so, can I ignore it, since it doesn't seem to be interfering with anything?