I read many different threads about folks having problems downloading comics directly to tablets... I have a Galaxy tablet that experienced the same - I could not download any comics with it, although I have no trouble with my laptop, so I did some experimenting. There were no options i could find in the generic browser that would cure the problem.
The answer (as best as I can describe it) in a nut shell: the Browser.
I think perhaps that browsers look at links differently. Observing that the android generic browser in my tablet was downloading these comic Zip files as 68kb html files, I decided to try other browsers. I tried Opera; it didnt work. Then I tried the android version of Foxfire and sure enough the comic books downloaded into my tablet via wi-fi, and it did not take forever. I use Foxfire in my laptop as well. With Foxfire for android the comic files went to a location that I did not expect - and that's something Ill be working on so they go to a place my tablet comics reader can easily find.
So, my answer, anyway, is to try downloading different browsers into your tablet and try them out one at a time.... you might get lucky like me.