Mail Doesn't Use Hyperlinks (sometimes)

[Ken]

I seem to have an odd problem with some of the mail I receive with 
Apple's Mail program.  Most of the HTML newsletters I get have links on 
them but Mail will not go to those links when I click on them.  I know 
they are viable links because the cursor changes to a finger when I 
roll over them.  Plus these same newsletters work fine using Entourage. 
  Do I have something set wrong?  There doesn't seem to be anything in 
Preferences that would affect this.

-= Ken =-