Easy one, just use the forums Search Engine
First copy the forum members ID that you want see posts from - ie: mine is CokeMann
Go to the top right of any page, then click where it says Advanced search
Then look for the section Search for author:
Enter the forum members ID into that part of the search engine
Finally click the Search button at the bottom of the page
The forums Search Engine will then give you a page with all posts by that member