I just had this occur to me as well in DoomRL 0.9.8.8B / WinXP.
In my case it was 2nd wave of monsters, the last monster (cacodemon) shot me while I was standing 1 square away, killing itself -> do you want to continue (y/n) -> answered yes -> crash
begin!!!" You hear screams everywhere! : "Kill, Kill, KILL!" Game saved.
Press <Enter> to exit.
A
n unhandled exception occurred at $0045CA27 :
ERangeError : Range check error
$0045CA27 TBEING__AISCAN, line 707 of dfbeing.pas
$0045CFCA TBEING__ACTION, line 776 of dfbeing.pas
$0045D153 TBEING__CALL, line 788 of dfbeing.pas
$0046647D TLEVEL__TICK, line 744 of dflevel.pas
$00410646 TDOOM__RUN, line 376 of doombase.pas
$00401920 main, line 21 of doomrl.pas
Abnormal program termination! Please write down the above
to help get rid DoomRL of all those bugs! You only need
to write down the filenames and linenumbers.
Attempting to save game.... Press <Enter>