The vBulletin search is good if you are looking for a single word. When you start doing boolean searches (multiple words), it gets bogged really fast. There are two comments I'll make that might help in the future.

First - if you know the person you were trying to find, then you can find that person's latest post by finding any post by that person. Simply search for their ID or look for them in the member list. If you click on their name on the left, a menu will pop-up with one of the options being to view their latest posts:

Name: vb_viewPosts.jpg Views: 102 Size: 46.4 KB

Second -
If you find the vBulletin search isn't working, then jump over to Google. Do the search with Google and add "site:VBForums.com" to the search. Google with then only search the site you list after the "site:" prompt. For example, you search on Google would have been:

full stack developer site:VBForums.com

If these don't answer your question, let me know. I'll need to look to see if the My Activity tab in the My Profile dialog shows latest ratings. The information might also be there if it was really recent.