After upgrading to lenny, I have the same problem. Looks like it is a rekeying problem.
Previously I was running a backport of 0.5.1r275-1 on etch, and this did not have the problem. I still had that .deb so I downgraded vpnc by installing it with dpkg, and the problem has gone away. This narrows down the breakage to sometime after r275. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org