Can not open Mail app since I updated the last version of Mountain Lion (10.8.2)
The correct version of Mail.app for OS X 10.8.2 (in my case build 12C60) would be 6.2, so your version is too old. Try software update, if that doesn't show anything reinstall the OS X 10.8.2 Combo Update manually. Run software update again after (re)installing this.