Hi all,
I'm trying to work through the Force.com workbook and during the "Call an Apex Class Method Using a Button" example, after going through all the steps, when I click the button, I get an error:

{faultcode:'soapenv:Client', faultstring:'No operation available for request
{http;//soap.sforce.com/schemas/package/InvoiceUtilities}
renumberLineItems, please check the WSDL for the service.',}

In my developer instance, I tested the Apex code in the developer console and it returns successfully.  I did research on google, and thought that it was either a permissions issue (I added everyone to the Apex class, no difference), or a Namespace prefix issue (i have namespace prefix 'bpavlyk;).  I confirmed that a WSDL was generated.

The code is straight out of the workbook (pages 79-81) but with add of prefix bpavlyk__ to custom fields and objects.

Here is the Apex class:

global with sharing class InvoiceUtilities {
    
	// Class method to renumber Line Items for a given Invoice number.
	// Returns a string that indicates success or failure.
	webservice static String renumberLineItems(String invoiceName) {

    // create a copy of the target Invoice object and it's Line Items
    bpavlyk__Invoice__c invoice = [Select i.Name, (Select Name From bpavlyk__Line_Items__r ORDER BY Name) 
                            From bpavlyk__Invoice__c i 
                           Where i.Name = :invoiceName LIMIT 1];

    // loop through each Line Item, renumbering as you go
    Integer i = 1;
    for (bpavlyk__Line_Item__c item : invoice.bpavlyk__Line_Items__r) {
      item.Name = String.valueOf(i);
      System.debug(item.Name);
      i++;
    }

    // update the Line Items in one transaction, rollback if any problems
    // and return error messages to the calling environment
    try {
      database.update(invoice.bpavlyk__Line_Items__r);
    }
    catch (DmlException e) {
      return e.getMessage();
    }

    // on success, return a message to the calling program
    return 'Line items renumbered successfully.';
  }
}

{!REQUIRESCRIPT("/soap/ajax/29.0/connection.js")}
{!REQUIRESCRIPT("/soap/ajax/29.0/apex.js")}
var result = sforce.apex.execute("InvoiceUtilities","renumberLineItems",{"invoiceName":"{!bpavlyk__Invoice__c.Name}"});
alert(result);
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