locale issues

[Tyler Littlefield]

Hello list,
I've got a quick question.
I get this with man, and mostly anything using perl.
svn: warning: cannot set LC_CTYPE locale
svn: warning: environment variable LANG is en_US.UTF-8
svn: warning: please check that your locale name is correct 
Obviously the program name isn't svn, but I"m a bit confused as to what this error means... Any ideas on fixing would be great, it's really annoying.