i also note a texture image in the Archicad 11 library "Metal perforated Alpha.png"
This implies that the file contains specific transparency qualities but it does not since it is saved incorrectly in the library.
PNG files support transparency masking without alpha channel since they can be saved as three channel files with transparent areas - like perfs.
Try using the attached file as your texture in the internal engine material dialog and checking transparency under alpha channel effects.
Dwight Atkinson