I have the latest firmware of FW:1.01.11 but everyday the last 4 days, the tunnels dropped at 5:31am and reconnects within a few minutes. There are 2 vpn tunnels, one for data and one for voice. Using 3des/sha1 with 28800 lifetime. Internet is going through the wan and voice is turned off and this workaround was used as well.
https://supportforums.cisco.com/docs/DOC-12874