Illegible Text In M$ Entourage


I regularly receive HTML emails from particular individuals that has garbled (unintelligible) text. I'm assuming this is likely a font issue, but I have no idea how to identify which font is causing the problems!

This happens on emails sent by SitePro News (among others) and I have a screenshot you can view here:

These emails always come from a trusted source (not SPAM) and are always domestic (no foreign language issues.)

Thanks for your help!
The text that appears illegible in your screenshot is uses specified fonts of MS Sans Serif, possibly Arial, or Helvetica. Make sure that your installations of Arial and Helvetica are OK.