1) I dont see a word saying that your search.php does not open once you hit search button. dont you think that would be a valuable information?
2) I dont see a word saying what version did you upgrade from.
3) make sure when you upgraded it you replaced ALL .php files
4) and finaly, if you want us test it, you should provide either with test username/pass or create a category were we can test it without login in.