Why in Classic ASP on Windows 10 a call to comp+ dll method generates error number -2147164123 with no description? - asp-classic

Question

I hope I am placing my question in right place. I could not find closer tags.
I am setting up a new 64 bit system to have everything from my old 32 bit system on it.
I used vb6 to create an activeX dll test project to make a testProj.dll, package it and install it by running the setup.exe of the package as administrator.
My test project is called testProj having a class called testClass which has a simple sub called testSub as follows:
Public Sub testSub()
Response.Write “--------- testSub is called ----------“
End Sub
The testSub simply prints a message to confirm that the sub was called.
I successfully install / register the testProj.dll and on an asp page I successfully call the Server.CreateObject(“testProj.testClass”) to instantiate the testProj for calling its testSub().
On Error Resume Next
Dim testObj
Set testObj = Server.CreateObject(“testProj.testClass”)
if err.number <> 0 then
Response.write "1----------err.number = " & err.number & "--------- err.description = " & err.description
err.clear
end if
Call testObj.testSub()
if err.number <> 0 then
Response.write "2----------err.number = " & err.number & "--------- err.description = " & err.description
err.clear
end if
Set testObj = nothing
But the code generates error with no description:
2----------err.number = -2147164123 ---------err. description =
Also if I comment out the 'Call testObj.testSub()' I do not get any error. Meaning that the source of the error is the call to testSub().
I run everything as administrator so I do not expect any permission issue.
Could an expert tell me what the problem might be?
Thank you

Answer 1

It looks like you are assuming that you have access to the Classic ASP context from inside the COM DLL which will not be the case. The code is failing inside the COM DLL because it doesn't know what Response is which will trigger an Object Required error inside the DLL bubbling up to the Classic ASP page.
The simplest solution is to change what the method is sending back. As you can't call the Response.Write() method directly the next best thing is to return a string instead then use Response.Write() from the ASP page to display it.
Modify the COM DLL method to return a String;
Public Function testSub() As String
testSub = "--------- testSub is called ----------"
End Function
Then in the ASP page;
Call Response.Write(testObj.testSub())