Problem on Xemacs

[Suchandra Thapa]

I'm using the Xemacs 21.4.14 on a Fedora Core 1 system.  When I load the
ess 5.1.20beta2 code or the 5.1.24 code, I get the following error: 

Fontifying region...(wrong-argument-type markerp nil)

This only occurs when input is occurring in the bar at the bottom.  It
can be reliable reproduced by typing C-x C-f and then typing a letter
and it occurs on each keystroke.    

The error does not occur if I prevent the ess code from loading. 
However, other than this ess seems to work without problems.  Is there
anything I can do to stop this error from occurring while using ess? 
Although the error doesn't affect functionality it is annoying since it
slows down input in that region.  

-- 
Suchandra Thapa <s-thapa-11 at alumni.uchicago.edu>