I downloaded your example from the article Display Word Document on web page asp.net
I'm showing the following error when i try to run it
System.Runtime.InteropServices.COMException:Unable to find the file (C:\Windows\system32\PROGRAMAS.doc)
And its supposed to be on this line :
applicationclass.Documents.Open(fileName, readOnlyObject, missingType, missingType, missingType, missingType, missingType, missingType, missingType, missingType, isVisible, missingType, missingType, missingType, missingType, missingType)