error message while calling fill-region to fill quoted text in reply

as suggested, a new bug report for this one...

> Good, vm-pcrisis didn't give the error. It looks like Emacs library
> fill.el might be at fault. VM has asked Emacs to fill the region
> between positions 391 and 1955. You can also probably try and do the
> same interactively. If it gives an error, then you should file a bug
> report with Emacs.

> Cheers,
> Uday

Hi Uday, I finally looked at this some more. I saved the email text into a text file, and called (fill-region a b) with a, b numbers that point to the empty lines with only ">" just before and after the main text paragraph. If I do this with a fresh emacs session called with -Q (not loading my settings) I don't get an error message. if I start vm, quit and try again outside of vm, I still don't get an error message. if I do this within vm, while replying to a message, I do get this error message. If I do this outside of vm, but after a reply in which I get the error message, I still do get this error message. I wonder if this has to do with some interference between vm-filling and emacs fill-region? some vm settings that stay in effect even after I quit vm? can you reproduce this error message? just to be clear, here is a typical text that leads to the error message:

 > Xxxxx Xxxx, Xxx, xxx Xxxxy,
 >
 >
 >
 > X fxw xxxxxxxx xxvx xxxx xxxy xxxx'x gxxxg xx xxx gxxxxxxx fxxxx
 > xxxp bxcxxxx xxxy'xx bx wxxkxxg xx xxxxx fxxxx yxxx xympxxxxm
 > xxxkx. X'x xxkx xx xxmxxx xxx xxxxx G1x xbxxx xxxx, xvxx xf xxx
 > xxxxx xxx xxxxxxxvx. Xx yxx xxxxk xx wxxxx bx xxfx xx xxxxmx xxx
 > xxxkx wxxx bx xxxxxx Mxxxxy & Xxxxxxy Xxpx. 13 & 14 xx Xxpx 20 &
 > 21? Xxxxx wxxx bx ~10 xxxkx xx xx wxxxx xxkxxy bx xvxx xwx xxyx.
 >
 >
 >
 > XB:
 >

and the error message and traceback are:

Debugger entered--Lisp error: (error "Invalid search bound (wrong side of point)")
  re-search-forward("\\([.?!][]\"'”)}]*\\($\\|[ ]$\\| \\|[ ][ ]\\)\\|[。．？！]+\\)[ \n]*$" #<marker (moves after insertion) at 820 in reply to xx> t)
  fill-delete-newlines(823 #<marker (moves after insertion) at 820 in reply to xx> left nil nil)
  fill-region-as-paragraph(820 811 nil nil)
  fill-region(393 812)
  vm-fill-paragraphs-containing-long-lines(window-width 309 1193)
  vm-fill-long-lines-in-reply()