<% Application("StoredArray")(3) = "new value" %>

This is because the Application object is implemented as a collection. The array element StoredArray(3) does not receive the new value. Instead, the value would be included in the Application object collection, and would overwrite any information that had previously been stored at that location.

It is strongly recommended that if you store an array in the Application object, you retrieve a copy of the array before retrieving or changing any of the elements of the array. When you are done with the array, you should store the array in the Application object again, so that any changes you made are saved. This is demonstrated in the following scripts.

---file1.asp---
<%
'Creating and initializing the array.
dim MyArray()
Redim MyArray(5)
MyArray(0) = "hello"
MyArray(1) = "some other string"

'Storing the array in the Application object.
Application.Lock
Application("StoredArray") = MyArray
Application.Unlock

Server.Transfer("file2.asp")
%>

---file2.asp---
<%
'Retrieving the array from the Application Object
'and modifying its second element.
LocalArray = Application("StoredArray")
LocalArray(1) = " there"

'Printing out the string "hello there."
Response.Write(LocalArray(0)&LocalArray(1))

'Re-storing the array in the Application object.
'This overwrites the values in StoredArray with the new values.
Application.Lock
Application("StoredArray") = LocalArray
Application.Unlock
%>

（出处：chinaasp）