Invalid timer warning

[Uday Reddy]

Tim Cross reports (vm.info, July 13, 2010):

I've noticed recently, particularly when running emacs 24, you
frequently get an "Invalid timer" warning when quitting VM. Note that
this does not throw an error or trigger a backtrace when debug on error
is on. The only way you know it has occured is by looking in the
*Messages* buffer. I only noticed it because emacspeak speaks all
messages, otherwise, it just flashes up in the mini-buffer very briefly
and is easily missed. I was going to log a bug report once I'd looked at
it and could provide a recipie to repeat it. It does seem less frequent
when you are only loading core VM. More frequent when loading some of
the add-ons, like vm-pgg.el
Tim