Sony PSR-T2 can't jumps to home screen when trying to go beyond page 31

Hi,

I recently bought Javascript Enlightenment but I can't read it on my Sony PSR-T2. As soon as I try to read beyond a certain page (I think it's page 31) , the screen turns black for a moment and then the reader displays the home screen. Flipping pages or navigating there by page number or table of content leads to the same result. Calibre can display the ebook properly. Since I have only this reader, I can't tell whether other readers have a similar issue.

A ePub validator by the way claimed, something is wrong with the CSS. No idea whether this is related.

Is this a known problem? Any solutione?

Thanks,
Gerd