you can get more information about iTextsharp tutorial(both C# version and VB.NET version ) from http://hardrock.cnblogs.com
Yeah - as long as you can understand this:
I think I might do it better:
"Subclass document"(this is not sure) is class constructer that have additional parameter that allow users to convienently changing the defined document path. So you can put this class package in any directory you have access to. Otherwise to use the class in the origional version, files of Chinese.php must be placed in the same directory of the class.