I'm trying to debug a VI application that uses a SQL server database. I'm
VERY NEW at using SQL Server.

In the ASP Application_OnStart, the connect string is setup:
Application("DBConnectString") = "DSN=MyDatabase;UID=sa;PWD=;"

This variable is passed to VB components that connect to the database. I
have checked the values of the VB objects from VI debugger, and the connect
string is correct. This same connect string works fine in VB client
applications hitting the same VB DLL component.

However, the ASP calls that use the database fail. In the application log,
I have an entry like this (application & computernames changed):

The VB Application identified by the event source logged this Application
XYZName: Thread ID: 3272 ,Logged: A SSDBMgr error occurred in module
'EmailType', in the method 'RetrieveEmailTypes', the error text is as
follows: [Microsoft][ODBC SQL Server Driver][SQL Server]Login failed for
user 'computername\IWAM_computername'.SQL=SELECT ID as 'ID', Description as
'Description' .....

Other hits to the database report a similar error except that user is
IUSR_computername instead of IWAM_computername.

What have I done incorrectly?