permissions needed for excel programming on asp web page

[tomthayer2]

We have a W2K3 server running IIS 6.0 and an intraweb ASP web
application that creates and downloads an Excel 2000 spreadsheet.
Security is set to "windows authentication" and a group of users
(WEBDW) are authorized. Excel 2000 is the only MS Office application
installed on this machine.

The following two extra permissions were made.

Component Services
DCOM Config
Microsoft Excel Application
Launch Permissions (add WEBDW)

c:\program files\microsoft office\office (permissions read/execute for
WEBDW)

This has been working fine for a long time.

There is a need to enhance this application. I'd like to add a macro
and a button. I did so with the following vbscript code.

=====================================================================
Const xlCellTypeLastCell = 11
Const vbext_ct_StdModule = 1
Dim rng,btn,vbmodule
set rng=ws(1).UsedRange.SpecialCells(xlCellTypeLastCell).Offset(0, 1)
set btn=ws(1).OLEObjects.Add("Forms.CommandButton.1",, _
False,False,,,,rng.Left,10,75,20)
btn.Object.Name="BtnSaveMark"
btn.Object.Caption="SAVE Mark"
With
xl.ActiveWorkbook.VBProject.VBComponents(WS(1).CodeName).CodeModule
.InsertLines .CreateEventProc("Click", Btn.Name) + 1, _
"call SaveMark"
End With
set vbmodule=xl.VBE.VBProjects(1).VBComponents.Add(vbext_ct_StdModule)
vbmodule.CodeModule.AddFromFile(homedir & "PartsLiability_Macro.txt")
=====================================================================

This works fine if you login to the web application as an administrator
for the web server. But it does not work for the WEBDW group.

The ASP error is "800a03ec, Cannot insert object". Event Log listed
actual errors of

Access denied attempting to launch a DCOM Server. The server is:
{D45FD2FC-5C6E-11D1-9EC1-00C04FD7081F}

and

Access denied attempting to launch a DCOM Server. The server is:
{000C101C-0000-0000-C000-000000000046}

I changed permissions in DCOM Config for

Component Services
DCOM Config
Microsoft Agent Server 2.0
Launch Permissions (add WEBDW)
000C101C-0000-0000-C000-000000000046
Launch Permissions (add WEBDW)

but now I got Event Log entries of

The Windows Installer Service was successfully sent a start control.

and

The Windows Installer Service entered the running state.

Further, Excel 2000 is messed up. When I do a Start Programs - Excel, I
get

There was a problem starting the Office Assistant. Would you like to
try reinstalling it?

I would not think I need any other Office components installed as
everything works when run by an administrator. It looks like a
permissions issue, but I am not sure what permission. Does anyone know
what permissions are required to run the above code from a web page?