http://www.abisource.com/bugzilla/show_bug.cgi?id=322
Two workarounds -- either rename the abi-0.5.0 directory to abi, or just 
move the libpng and zlib libraries into the 0.5.0 tree.  
How embarrassing.  We debated sneaking out another set of 0.5.0 tarballs with 
the necessary fix, but trigger-happy folks have already downloaded it, so we 
decided to let it stand. 
Paul
PS:  No, we *won't* be walking around LinuxWorld with bags on our heads.  
It's not *that* embarrassing.  :-)