Well, it is really weird, let me describe the problem again...
1. In Safari, I put this:
http://x.x.x.x.:8080
2. Then, all my collection is displayed in Safari Browser, no issues
3. I select any book and click on "epub" hyperlink
4. The page got refreshed and two options or buttons appears: one for open via iBooks and the other button is "open with" or something like that, iBooks is an option on that button plus Goodreader
5. I select iBooks (or the other one, iBooks as well)
6. Then iBooks opens.
7. Upper left corner started showing internet activity. On my Ubuntu Laptop I can see that the file is being uploaded.
8. Like 2 or 3 seconds the Internet Activity animation stops on my iPad
9. Nothing on the iBook....no book...no cover...no nothing...
Some specs:
-My book collection resides on an Ubuntu Lucid headless server (but I also tested moving that to the laptop)
-My Laptop, the one who runs Calibre, is running Ubuntu Linux / Lucid
-Calibre version 0.6.42
All machines are on same private network: 192.168.1.x and they see each other with no issues.