Webservice problems.

Hello. I am desperately trying to send data from a client application to a webserver via a webservice. Apparently I cannot pass an object class as a parameter, so have decided to use a dataset. When I run the code, I get the following error at this line in Reference.vb:Dim results()AsObject =Me.Invoke("SendSpecs",NewObject() {serial})

An unhandled exception of type 'System.Web.Services.Protocols.SoapException' occurred in system.web.services.dll

Additional information: Server was unable to process request. --> Object reference not set to an instance of an object.

This occurs even when I simply request a dataset from the webservice. Here is the code for my webservice.

<WebMethod()>PublicFunction SendSpecs(ByVal serialAsString)As DataSet

Dim dsMainAs DataSet

Dim cmdAs SqlCommand =New SqlCommand

Dim paramAsNew SqlParameter

dsMain.Clear()

cnMain.Open()

cmd.CommandText = "Select * From PCSpecs Where SerialNo = @SerialNo"

param.ParameterName = "@SerialNo"

param.Value = serialNo

cmd.Parameters.Add(param)

cmd.Connection = cnMain

Dim daMainAsNew SqlDataAdapter(cmd)

daMain.Fill(dsMain, "PCSpecs")

cnMain.Close()

Return dsMain
I call the code client side by:dsSpec = WMIservices.SendSpecs(serial). Can anyone help me with this? I have been trying for ages, and really need this to work.

Thanks,
Robert

[2968 byte] By [hoffi] at [2007-12-23]