What is "XML-file failed validation against schema" error?

 When I change the current directory manually in 2009b using the
 toolbar into a particular toolbox, I get the following error:

 "XML-file failed validation against schema located in:
 C:\Program Files\MATLAB\R2009b\sys\namespace\info\v1\info.xsd"

 What does this mean? I don't see this error with any other toolbox> that I recall.

he error message is trying to tell you which info.xml file failed, where the schema file lives that we validate against, what the errors are, and how to re-test the file after making changes.