ePub reader shows ePub files content's font sometimes Bold sometimes regular

I have made one application in which I implemented ePub reader which unzips file and parses xml file. I have adopted method of this question on S.O. Reading ePub format .

The code was working fine till today before I replaced .ePub files with client's updated files. After replacing .ePub files I ran application on simulator and I was shocked as ePub reader shows all file's content in BOLD format randomly, I mean assuming there are 5 .ePub files in application sometimes it shows file 2,3 content in BOLD sometimes file 1,4,5 content in BOLD. I could not figure out the problem so I replaced those files with older ones and problem disappeared..

Following the apple guidelines http://support.apple.com/kb/HT4168. I recommended client to use Pages '09 to export ePub files. So is it the problem with coversion using Pages '09? because I have opened all .ePub files in stanza and calibre and contents were not i开发者_开发技巧n BOLD format. So I can't figure out wether its a conversion problem or coding problem.

Code I used for reading ePub files(Maybe it will help): http://pastebin.com/dY4CFetU

Thanks..

It is quite probable from your description that the problem resides in the provided ePub files. Try validating the ePub with an ePub validator, like this one. You should then be able to find the mistake in the xml.