Ok, no worries, this is all part of the learning curve...although it is a bit of a :banghead: situation.
Had you have mentioned the errors earlier, ie post #1, it would have saved us running around trying to find files, solutions etc etc.
The PSD file uses 'Smart Filters', (Filters applied to Smart Objects), but these were not introduced until recently, hence you get the error when CS2 tries to read a layer containing a 'Smart Filter'....like 'bookCover copy 3'.
Anyway, enough of the history lesson, 'normally' when you edit a Smart Object it will open as a temporary PSB file....but that file itself 'could' contain any number of other 'Smart Objects', embedded psd files, jpgs, png's, whatever...and so it could go on.
Well, er, yes....didn't I say that back in post #12? LOL.
If you want to check it yourself open the file, (as best you can), and use FILE > File Info...(CTRL + ALT + SHIFT + I).....down the bottom you'll see the application that saved the file...Adobe Photoshop CS4 Macintosh.
Ho hum.
Regards.
MrToM.
EDIT:
And after reading your other thread you'll be able to open it....without any errors! 
