autofill - wrong number of arguments when refilling paragraph

[Rares Vernica]

Hi,

I am editing a .tex file and the auto-fill-mode is on. When trying to 
refill a paragraph I get:
Wrong number of arguments: #<subr set-match-data>, 2

Anyway, it seems that if there is an empty line before the paragraph 
everything works fine.

For example, is instead of:
  \begin{abstract}
    bla bla

I have:
  \begin{abstract}

    bla bla

it works.

Is the empty line before the paragraph a requirement for the refill 
command to work?

Thanks,
Ray