That error says that your Tab is disconnecting in the middle of sending a book. This is precisely the error that we (though we) fixed.
Sorry to ask the obvious, but did you install the updated app from google play?
Does the progress dialog (not the spinner, but the books transfer progress dialog with two progress lines) still show on the Tab when the error occurs? There is a problem where touching the screen while the progress dialog is showing will break the connection. Given the calibre error the progress dialog box should still be there.
Is it possible that the SD card on the Tab is full?
If you are willing, could you re-initialize the app? Go to settings, apps, Calibre Companion, and touch "Clear Data". This will erase all the books on the app that calibre companion has downloaded, as well as CCs book database. While in apps, could you verify that you have version 1.1? The version number will appear just below the "Calibre Companion" line at the top.
After having pushed the Clear Data button, start the app and connect to calibre. Transfer 4 or 5 books, not 100. If that works, then transfer 4 or 5 more. If that works, then transfer the same 8 to 10 books again. Let me know what happens.
NB: I have transferred 60+ books at once around 20 times to my Galaxy Nexus, so the problem isn't simply the number of books. Something else is going on.