I am sorry you were not able to find your forum post. You can find posts you have made in a variety of ways. One way is to go to your profile, and follow the "Topics" link on the left-hand navigation column. Another way is to search for your post by clicking the magnifying glass in the upper right. In case you are still not able to find your post, here is a hyperlink to Nathan's response.
Also, by default, forum members should be getting email notifications when they get replies except during times when they are actively browsing the forum. You can find the email settings under the "Preferences" tab of your forum account.