This is my code:
global class ExtractDataFromPaypal implements Messaging.InboundEmailHandler {

    global Messaging.InboundEmailResult handleInboundEmail(Messaging.inboundEmail email,

    Messaging.InboundEnvelope env) {

        // Create an InboundEmailResult object for returning the result of the  

        // Apex Email Service 

        Messaging.InboundEmailResult result = new Messaging.InboundEmailResult();

        try {

            // Add the email plain text into the local variable  

             string myHtmlText = '';

             myHtmlText = email.htmlBody;

            

            string rst;

            string Address;

            string a1;

            string a2;

            

            //CustomerName

             Pattern p4 = Pattern.compile('Buyer\\s*information[\\s\\S]+?<br>([\\s\\S]*?)</font>');

            Matcher m4 = p4.matcher(myHtmlText);

            if (m4.find()) {

             rst = m4.group(1).replaceAll('(<[^>]*>)','');          

            }

            

            //Physical Address

            Pattern p1 = Pattern.compile('<b>\\s*Ship-to\\s*address\\s*</b>\\s*-\\s*<font[^>]+>\\s*Confirmed([\\s\\S]*?)<br>\\s*</span>');

            Matcher m1 = p1.matcher(myHtmlText);

            if (m1.find()) {

                a1 = m1.group(1).replaceAll('(<[^>]*>)',''); 

                a2 = a1.replaceAll('&nbsp;','\t');

                Address = a2.replaceAll(rst,'');

            }

            // New PaypalRecord object to be created - set Shipping_Address__c and OrderNumber etc. to object

            // dummy values for simplicity

            PayPal_Record__c record = new PayPal_Record__c(CustomerName__c = rst, Shipping_Address__c = Address

                                                    );

            // Insert a new record

            insert record;

    

        } catch (Exception e) {

            result.success = false;

            result.message = 'Oops, I failed!' + e;

        }

        // Set the resul　t to true. No need to send an email back to the user      

        // with an error message   

        result.success = true;

        // Return the result for the Apex Email Service 

        return result;

    }

}


So my problem is : when i debug this code, everything is fine, it can running successfull and all the data i grabed from email can entry in database,,,,,but when i running in real environment which i use email service,,,,,, then i will received an email and told me : 
Oops, I failed!System.StringException: No match found

why?   please give me some idea and suggestion.
Thank you anyone who can help me.....:)