xml validation and &amp entity

[Raphael Summers]

Hi,

It appears that my simple xml document cannot validate successfully on typing 
C-c C-v. 

It complains as follows:

nsgmls:fos_human.xml:7:54:E: general entity "amp" not defined and no default 
entity

I am under the impression that I should not have to define &amp (&apos also 
does not appear to work). Why is it not able to detect the defaults entities? 
Am I inadvertently missing a line of code? The xml code parses correctly on 
Mozilla and the ampersands appear. Additionally, my xml validates 
successfully at http://www.stg.brown.edu/services/xmlvalid

Please reply to my own email address. 

Thanks in advance,

Raphael Summers.