Unable to save a mail attachment via applescript

Question

I am attempting to use the following script as rule in mail to save attachments. It appears to do everything correctly except saving attachments. Advice / help most welcome. Thank you.
using terms from application "Mail"
          on perform mail action with messages theselectedMessages
                         tell application "Mail"
                                        repeat with theMessage in theselectedMessages
                                                       set senderName to extract name from theMessage's sender
                                                       repeat with theAttachment in theMessage's mail attachments
                                                                      set originalName to name of theAttachment
                                                                      set folder_path to "/Users/xxxxx/Documents/Temp/" & senderName & " - " & originalName
                       set file_path to (folder_path)
                                                                      try
                            save theAttachment in file (file_path)
                                                                      end try
                   end repeat
                                        end repeat
                         end tell
          end perform mail action with messages
end using terms from

Answer 1

The saved files need to be uniquely named. See:
http://www.macosxtips.co.uk/index_files/automatically-save-mail-attachments-usin g-applescript.php
my latest version:
(* While this script worked, it didn't run reliably in Tiger 10.4.11.  Mail would crash at randomn times. *)
using terms from application "Mail"
    on perform mail action with messages theselectedMessages
        display dialog "we have arrived in mail save...." giving up after 4
        try
            tell application "Mail"
                repeat with theMessage in theselectedMessages
                    set senderName to (extract name from theMessage's sender)
                    repeat with theAttachment in theMessage's mail attachments
                        set originalName to name of theAttachment
                        set oName to originalName as string
                        set sName to senderName as string
                        set folderPath to (path to documents folder) as string
                        display dialog "we have initial class " & class of folderPath & " with " & folderPath giving up after 4
                        set folderPath to folderPath & "Temp:" & sName & " - " & oName
                        display dialog "we have class " & class of folderPath & " with " & folderPath giving up after 4
                        try
                            display dialog "saving " giving up after 4
                            -- Please note the saved files need to have a unique name else you
                            -- will get an error message "NSInternalScriptError"
                            save theAttachment in folderPath
                            display dialog "We saved the file!" giving up after 10
                        on error errorCode
                            display dialog "mail save received an error. " & errorCode
                        end try
                    end repeat
                end repeat
            end tell
        on error errorCode
            display dialog "mail save app received an error. " & errorCode
        end try
        set rc to 0 -- make sure to return a zero return code
        -- Applescript returns whatever was last set.
    end perform mail action with messages
end using terms from