I am getting this stacktrace:
System.Runtime.InteropServices.COMException (0x800A13E9): Word ðú÷ì ááòéä.
at Microsoft.Office.Interop.Word.Documents.Add(
Sorry 'bout that 1MB reference... I just had to jump on that one.
When automating Office Applications make sure, that you use a local account on the server with permissions for the Word COM+ object as well as the documents you are trying to work on.
There are several posts relating to your problem pointing at the account issue: