I use OOo 1.1.3 with Windows XP to create a new document in which I embed PNG
graphics (no link). I save this document as a Microsoft Word 97/2000/XP document.

I then send the .doc file to my colleague, who opens it with Microsoft Word (I
am not sure which version he is using, but it is a recent one), on a Mac running
MacOS X. The graphics usually appear completely black, or with a black background.

Note that this problem does *not* happen with Word 2000 or XP under Windows. It
only happens on Macs.

Now, we managed to find out that the problem was due to the fact that my graphic
files were using transparency in their background. I replaced the transparent
background with a plain white background and the graphics appeared correctly on
the Mac.

This being said, I am not sure where the problem lies:

(a) with OOo? More specifically, the way OOo exports graphics using transparent
background.

(b) with MS Word on the Mac? More specifically, the way Word imports graphics
using transparent background.

(c) with the program I use to save the graphics (it is Inkscape), which  maybe
saves the file in a corrupt format? However, I opened the graphics with GIMP and
they looked fine, so I don't think there is a problem there.