history search trouble

[Evil Boris]

I am running a reasonably recent CVS Emacs.  A couple of weeks ago,
after an update, two things broke:

-- send-mail-function's value went to nil; doing a "make bootfast"
   cured that.  Did not look into it again.

-- history search broke, in all context where I use it.  I just tried
   it again: invoked several nonsense commands via M-!, then tried M-!
   M-r something RET and got back a beep with "No previous history
   search regexp". *Messages* Buffers looks like this:

gibberrish: Command not found.
garbage: Command not found.
nonsense: Command not found.
if: No previous history search regexp

   Enabling debug-on-error has no effect.  Neither does "make
   bootstrap", which is a fairly slow exercise on my machine. 

Ideas?  [For the record, Solaris 7 on Ultra60, gcc 3.1.]

Any help would be appreciated.

    --BA