[Zope] why this link is not working properly?

[Jianping Zhu]

I have redhat 7.1 box with zope on it.
I have a link to a microsoft .pdf 
file,

http://coopunit.forestry.uga.edu/unit_homepage/Conroy/projects/pnwr_arm/new_arm.html 
in the lower part

links:
2000
1999
1998
1997
1996

link 2000 works fine
but 
when i click 1999 (WebBouser), the pdf file does not appear. how can i settle this 
problem?

Thanks