Thanks for the insight on the different (!) 2007 viewers and the note about
back-saving.
Having downloaded PPT Viewer 2007 from MS I nevertheless have the shifted
text problem. It appears that when I change the position of marked text by
sliding the indent markers on the ruler that this SOMETIMES does not
translate. Likewise the automatic settings for a bulleted list in 2007 seem
to be lost and the text is just smashed up to the left as if the settings
were not there at all. Is this a bug or do you know the cure?

Also, the shadows around the graphics and text titles (for example white
sharp shadows instead of the diffuse grey ones in 2007 and without the mirror
effect entirely) looked different than in 2007. Do you know if the newer 2007
viewer is really 100% 2007 compatible or should I expect these differences
and that is just the way it is?

Since my goal is to share with pre 2007 users, I went ahead and tried saving
to 2003 format and then using the 2003 viewer to see if it worked (we no
longer have any machines running PPT 2003 here to test on) and in the 2003
viewer all the text is gone. The shading of the text boxes is there however,
as are my graphics (screenshots).

I  repeated the convert to 2003 process with other presentations just to see
and have 1(!) slide which works. Strangely, in this presentation, when I
selected "save as 2003/ppt" I received a warning that the text in this
particular slide would not be editible. But it is the only slide that shows
text when displayed in the 2003 viewer!

I tried creating new slides in the 2003 ppt file while in 2007 compatibility
mode but these new slides do not display text in 2003 mode either, but the
text does appear in viewer 2007.

Any hints on my various issues?
Thanks for all your help!