I''ve installed ruby4skype. I have tried a simple function with the methods found from the ruby4skype gems'' lib/sms.rb, trying to send a sms: @sms_targets =[''+852123'', ''+852456''] @sms_id, @sms_status = Skype::SMS.create @sms_targets.first, ''OUTGOING'' @sms_body = ''testing message'' logger.info "created #{@sms_id} #{@sms_status}: body #{@sms_body}" Skype::SMS.set_target_number @sms_targets Skype::SMS.set_body(@sms_body) Skype::SMS.alert_sms @sms_id , ''SEND'' HOWEVER, it failed at the very beginning " Skype::SMS.create ". With the error: undefined method ''invoke'' in the sms.rb.