Have you ever done a search for files containing specific text with Windows Explorer and have it return no results even though you know that the files are there? Well, if you're using XP, chances are the problem is that XP only returns results for files whose extensions have a "PersistentHandler" value in the registry. It's documented in a MS tech note on the issue.
Why do you care? Because the PowerBuilder source code extract files don't have such values, unless you create them. Fortunately, one of the MS MVPs has a utility that restores the typical "search all files" results one gets from the earlier operating systems.