I have a VB COM obj residing in IIS that upon ASP web client request
calls a function from a VC++6.0 DLL, in the following manner:

"
Dim obj As New app_objects.clsFunction()
obj = Server.CreateObject("app_objects.clsFunction")
strResultsTable(0) = obj.Function(txtInput.Text, param1, param2)
Marshal.ReleaseComObject(obj)
"

This works for a single client call. If a second client requests the
service when the first has not finished, IIS outputs the following
error to the second client:

"
Object reference not set to an instance of an object
"

The first client does not get any errors and receives the correct
answer to his query. If the second client requests the page after the
first client completion, there is no problem.

I have tried apartment model, unattented execution and retained in
memory option, but unsuccessfully. Is it a VC DLL error, an IIS
problem or a COM setting?

Thanks in advance for your support and help.