libpng-1.5.2 on i686

Hello World!
I compiled ImageMagick-6.6.9-3 with --prefix=/usr --disable-static and
it linked against the already installed libpng-1.5.2. 
On x86_64 it all works as expected, i can use convert to make a jpeg 
into a png, I can use display to show a png.

On i686, however, it doesn't work. If I try to convert an image into a
png it just hangs, nothing is produced, no error in the terminal, the
cpu is not used. If I try to display a png it opens a window with the
ImageMagick logo and prints this in the terminal:

andy:~$ display mountain-fox.png
display: memory allocation failed `mountain-fox.png' @ error/png.c/ReadOnePNGImage/1672.
display: corrupt image `mountain-fox.png' @ error/png.c/ReadPNGImage/3227.

Although ImageMagick compiles against the current version of libpng, on
i686, it doesn't seem to work.

Andy