These are coming when the tunnel drops, I would normally say there was a miss-configured endpoint or IP typo but the tunnel comes up and is fairly stable, it looses about 30 seconds every 8 hours, but unfortunately this is to much for the tunnels purpose.
If you are using an ASA running software version 7.1 then it is bug CSCse29700. WebVPN and SSL VPN Client sessions to an ASA running software version 7.1 are intermittently disconnected As a workaround, perform either of these steps:
Reload the Cisco Adaptive Security Appliance (ASA) until the issue is resolved.
Download and upgrade the ASA software to any one of these versions: