I easily emailed my chat history to my email address. Try this, open the chat of contact you want to email. For example if you want to email history of contact ABC to your email address, open chat of ABL. In option, select email conversation, wait if you have that long history, after some time, your email accounts (you have registered on your phone) will appear. For example, I have installed Yahoo mail application along with default Gmail. After selecting the option, "Email conversation", mobile will give you option, you want to email through which account, Yahoo or Gmail (in my case), select you desired email account and input the email address; I gave my own. And press send.
You may be facing problem due to following reasons:
Make sure you have some email option installed in your handset, for example Yahoo mail.
Make sure you have enough phone and card memory available to execute this process. I LL try it hope it works thanks a lot

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