That solved it... I had less than two pages of home screen, but several folders with quite a few links inside. I cleaned out several of the folders, and I can now save to the Home Screen again! Also, DocuShortcut works again.
My last questions still stand, however- anyone know what the limits are for Home Screen shortcuts? I really don't think I should have been near "too many", but it looks like I'll need to be a bit more creative with how I link...
Thanks again for the help!
-mike