I dont know if this helps, but I was looking to print out a stock report or get in an exce file as well, and I realized that since the reporting function of zen cart only shows 20 items per page (and has no option to show all on one page), it is a problem if you wanted to view it all on one page.
Of course once you can view it all on one page you can simply hit print from internet explorer and it would print all stock report as displayed on the screen OR you could highlight all the products using your mouse and then do a copy/paste into excel (it worked in my excel version 2007).
So I dowloaded a module called "INVENTORY REPORT" (I did not find it on zencart webite, I did a googe search for "zencart inventory report" and it was the first link).
This allows you to show all product in one page and then use the methods I mentioned above to either print or copy/paste into excel.
Hope this helps...
P.S. I am using the invetory report module on zen cart 1.3.7 and it seems to work fine.