Application.FileSearch didn't work in Office 2007 (It has been deprecated from Office 2007) and hence it doesn't work in Office 2010 either. It will throw Run-time Errror 445 Object doesn't support this action
There are some good work-arounds for this:
1. FileSystemObject
2. Dir Function
For a lively discussion please have a look at http://social.msdn.microsoft.com/Forums/en/isvvba/thread/a450830d-4fc3-4f4e-aee2-03f7994369d6
Excel 2010 Application.FileSearch Error, Excel 2007 Application.FileSearch Error