There is such mistake if in a theme it is more than pages 20 by pressing the reference showing all of page, nothing occurs - empty page and a mistake. An example
http://forex.kbpauk.ru/showflat.php?Cat=0&Board=flame&Number=871&page=0&fpart=all

Yes, I've noticed this on other pages. It's a rounding error somewhere in the pagination routine. While there's no official bug for this issue at this time, we'll file one some time in the relatively near future.