In your personal profile area (My Controls) link at top of the page, scroll down and near the bottom left column is OPTIONS and there, hit the email option button.

You'll see multiple choices in your email profile preferences to get notification of a reply to a post (subscriptions) notices of PMs etc.

Click the appropriate boxes for what and how you get notices.

If those are not working, please let me know so I can swat the programmer's backside.