This issue is about how a stylesheet is causing an epub file to not work on a KOBO.
I have packaged my epub files with epub packager 1.3.2. and validated with epubchecker 1.1.1.

The epub file displays on a computer epub reader but when loaded onto KOBO, does not get past the cover of the book. However if I rename the arrest.css file to "Arrest.css" and load it (with the error that it is missing the css file due to case sensitivity), it works on the KOBO, but has no style sheet.

Somehow, the stylesheet appears to be contributing to the freezing of the KOBO. Any help would be appreciated.

Here is the css line in the manifest:
<item id="css" href="arrest.css" media-type="text/css" />

Here is the line in the xhtml file:
<link href="arrest.css" rel="stylesheet" type="text/css"/>

You will have to show us the css file before we can (have any chance to) figure out what the problem is.

And if it is to large to upload, with lots of repetitions, that may be the problem.

2nd edit - Does your css file validate using http://jigsaw.w3.org/css-validator/ ??

Pholy, I agree that probably his CSS does not validate.

And I also have to agree. Thanks.