A bad character in the html can cause the reader to crash even though it reads fine on the computer. I've experienced this with some ePubs I made using Atlantis - a manual page-break before an h1 tag leads to it inserting an invalid character code at the start of the chapter title. When I remove the bad characters using Notepad++ the ePub works fine.
Katelyn, the ePub you uploaded has references to 'index2.html' in the toc and several of the html files. Since this file doesn't exist inside the ePub that may be what's causing problems on your reader.
If you have problems reading a certain book, I really recommend checking the ePub with ePubcheck
as it's far more likely that it's the code that's at fault rather than your reader. ePubCheck often spits out a load of errors on books that read fine. Basically errors of the type 'attribute "qwert" not allowed at this point; ignored' can be disregarded, but 'could not parse toc.ncx: Invalid path' is more serious as are errors that report an invalid XML character.