XnView version 2.00 (April 11, 2013) crashes after opening PNG pictures that were created by the CAD program UG NX 7.5: http://couzijn.125mb.com/err_png.html
No idea what's wrong, they open in other programs and in previous versions of XnView, and other PNGs work fine in XnView.
I'm having the same issue; a sample image can be found below (24-bit RGB PNG, background color (58,110,165)): http://couzijn.freehostia.com/sample.png (copy-paste the address to bypass the web hosting nag screen) Remarkably, in batch processing the Auto crop transformation does work as desired ...