I seem to be unable to find a solution to this error. These field names exist in my enterprise wsdl, though if I try to set them, the creat call fails with that error message.

Any advice?

Here is my function:

    private void createTheFollowUpEvent()
    {
        //Create an event object to send to the service
        Task myTask = new Task();
        //Set several properties
        myTask.WhatId = opportunityID;
        myTask.WhoId = ContactID;
        myTask.IsReminderSet = false;
        myTask.ActivityDate = cldCloseDate.TodaysDate.ToUniversalTime();
        myTask.Description = txtCallSubject.Text;
        myTask.Subject = "Follow up call";
        myTask.OwnerId = userId;
        myTask.Status = "Completed";

       
        // Add the account to an array of SObjects
        sObject[] records = new sObject[] { myTask };
        // Invoke the create call, passing in the account properties
        // and saving the results in a SaveResult object
        SaveResult[] saveResults = binding.create(records);
        // Access the new ID
        String newID = saveResults[0].id;

       
    }
    private void createAnotherEvent()
    {
        //Create an event object to send to the service
        Task myTask = new Task();
        //Set the properties
        myTask.WhatId = opportunityID;
        myTask.WhoId = ContactID;
        myTask.IsReminderSetSpecified = true;
        myTask.IsReminderSet = true;
        myTask.ReminderDateTimeSpecified = true;
        myTask.ReminderDateTime = cldFollowUpDate.SelectedDate.ToUniversalTime();
        myTask.ActivityDate = cldFollowUpDate.SelectedDate.ToUniversalTime();
        myTask.ActivityDateSpecified = true;
        myTask.Description = txtTaskSubject.Text;
        myTask.Subject = "Follow Up on " + quoteNumber;
        myTask.OwnerId = ownerID;
        myTask.Status = "Not Started";


        // Add the account to an array of SObjects
        sObject[] records = new sObject[] { myTask };
        // Invoke the create call, passing in the account properties
        // and saving the results in a SaveResult object
        SaveResult[] saveResults = binding.create(records);
        // Access the new ID
        String newID = saveResults[0].id;

    }

I seem to be unable to find a solution to this error. These field names exist in my enterprise wsdl, though if I try to set them, the creat call fails with that error message.

Any advice?

Here is my function:

    private void createTheFollowUpEvent()
    {
        //Create an event object to send to the service
        Task myTask = new Task();
        //Set several properties
        myTask.WhatId = opportunityID;
        myTask.WhoId = ContactID;
        myTask.IsReminderSet = false;
        myTask.ActivityDate = cldCloseDate.TodaysDate.ToUniversalTime();
        myTask.Description = txtCallSubject.Text;
        myTask.Subject = "Follow up call";
        myTask.OwnerId = userId;
        myTask.Status = "Completed";

       
        // Add the account to an array of SObjects
        sObject[] records = new sObject[] { myTask };
        // Invoke the create call, passing in the account properties
        // and saving the results in a SaveResult object
        SaveResult[] saveResults = binding.create(records);
        // Access the new ID
        String newID = saveResults[0].id;

       
    }
    private void createAnotherEvent()
    {
        //Create an event object to send to the service
        Task myTask = new Task();
        //Set the properties
        myTask.WhatId = opportunityID;
        myTask.WhoId = ContactID;
        myTask.IsReminderSetSpecified = true;
        myTask.IsReminderSet = true;
        myTask.ReminderDateTimeSpecified = true;
        myTask.ReminderDateTime = cldFollowUpDate.SelectedDate.ToUniversalTime();
        myTask.ActivityDate = cldFollowUpDate.SelectedDate.ToUniversalTime();
        myTask.ActivityDateSpecified = true;
        myTask.Description = txtTaskSubject.Text;
        myTask.Subject = "Follow Up on " + quoteNumber;
        myTask.OwnerId = ownerID;
        myTask.Status = "Not Started";


        // Add the account to an array of SObjects
        sObject[] records = new sObject[] { myTask };
        // Invoke the create call, passing in the account properties
        // and saving the results in a SaveResult object
        SaveResult[] saveResults = binding.create(records);
        // Access the new ID
        String newID = saveResults[0].id;

    }