I have downloaded a few books from Project Gutenberg, and none of them opens in Readium. The progress bar starts and hangs as soon as it starts.
I do not think the files are corrupt, I tried them with Firefox's EPUB Reader and they are fine.
Also I tried to open a book from Manybooks.net (http://manybooks.net/titles/englandc2962229622.html) and I got a message "Error writing on disk." There is enough space on my hard drive that is strange. It turned out it works fine in Firefox EPUB Reader as well.
-
Readium 0.5.3
Chromium Version 20.0.1132.47 Built on Ubuntu 12.04, running on LinuxMint 13 (144678)