I am getting the following error from my FORM code:

'Cannot implicitly convert type 'int' to 'string' which refers to the following line of code in my FORM code:

lblCount.Text = il.load( Convert.ToInt16(lstringClientID), lintMonthText, Convert.ToInt16( lstringYearText ));


My FORM code:

private void btnInvoiceSearch_Click(object sender, System.EventArgs e)
{
    Cursor.Current = Cursors.WaitCursor;

// Identify the variables from the form elements to pass to the stored procedure in the PSSBilling_WebService
    string lstringClientID = txtClientID.SelectedText;
    int lintMonthText = lstMonthText.SelectedIndex + 1;
    string lstringYearText = lstYearText.SelectedItem.ToString();

    InvoiceList il = new InvoiceList();
    lblCount.Text = il.load( Convert.ToInt16(lstringClientID), lintMonthText, Convert.ToInt16( lstringYearText ));
}

My LOAD code from another class within my same project:

public int load (int astringClientID, int aintMonthText, int astringYearText)
{
    iintClientid = astringClientID;
    iintMonth = aintMonthText;
    iintYear = astringYearText;

// Connect to the PSSBilling_WebService
    PSSBilling.Service1 wsSearch = new PSSBilling.Service1();
    idsInvoices = new DataSet();
    idsInvoices = wsSearch.getInvoiceDataByClient( astringClientID, aintMonthText, astringYearText );

    return idsInvoices.Tables[dsReturnedData].Rows.Count;
}

The Load method return an integer:

public int load (int astringClientID, int aintMonthText, int astringYearText)

Your call to it is trying to stuff the result (an integer) into a string. You need to convert the int to a string:

lblCount.Text = Convert.ToString(il.load( Convert.ToInt16(lstringClientID), lintMonthText, Convert.ToInt16( lstringYearText )));

or

lblCount.Text = il.load( Convert.ToInt16(lstringClientID), lintMonthText, Convert.ToInt16( lstringYearText )).ToString();