I created a TaskSpace application and imported two documents in "My Folder": a .JPG file and a .PDF file.
First, i access the .PDF file; no problem.
Second, i try to open the JPG file, and the first error, "File: <name.jpg> Invalid File" (see first attached image), arises. This dialog appears two times. At last appears a second message "Tried all the URLs for an document. None sucessful.". I click OK. If i try to open again the JPG file, it opens normally!