rsync - May 2002 - malformed address

Hello,

I've been getting quite a few "malformed address" messages
in my rsync log, but the host name it lists appears fine to
me.  I think this message is coming from the access.c file,
but am not sure what conditions trigger it.  Could someone
give me a few pointers on why I would see this and possibly
how to correct it?

Thanks!

Brad