You are downloading the Letters XAP file v220.127.116.11 for Windows Phone. Letters is a free and useful Kids & Family app: Download the cutest love app ever and show that special person how you feel about them. Talking Tom and Talking Angela are at hand to help ... You can now download the offline XAP file to install & try it.
Download Locations for Letters 18.104.22.168 XAP file
To try to install it manually from an SD card, you should choose one of the server location above to get the offline Letters XAP file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.