Fix

<..bib in amsppt.sty..>+
 \def\makerefbox#1#2#3{\endgraf
   \setbox\z@\lastbox
   \global\setbox\@ne\hbox{\unhbox\holdoverbox
     \ifvoid\z@\else\unhbox\z@\unskip\unskip\unpenalty\fi}%
   \egroup
   \setbox\curbox\box \@ne
   \ifvoid#2\else\Err@{Redundant \string#1; duplicate use, or
      mutually exclusive information already given}\fi
   \def\curbox{#2}\setbox\curbox\vbox\bgroup \hsize\maxdimen \noindent
   #3}
 -_-_-

The original file has the code ‘\setbox\curbox\box \ifdim\wd\@ne>\z@ \@ne \else\voidb@x\fi’. That code is problematic because we can reach widths larger than can be measured by the ‘\wd’ command.