As PHP can generate dynamice content you need to turn off Joomla's caching. I included some PHP code that retrieves information from another database, with paging and a search box. With caching Joomla enabled you will only see the first page and no paging nor search will make difference in that.

I will report this as a bug to the authors, but I don't know if Joomla allows deactivating cache for one specifice page.