[VE][libxml2-205] Confused about validation error: colon are forbidden from entities names 'CWM:ChangeableKind'

Hi,

validating
http://hrview.de/measures/index.php/xml/generate/dd5ea5c4-4e48-4e9b-8d44-91a75694ef74
(i have attached the xml) i get many errors of the following kind:

colon are forbidden from entities names 'CWM:ChangeableKind'

<!ENTITY % CWM:ChangeableKind '(changeable|frozen|addOnly)'>


Looking in the XMLSpec (esp. the reguarding names):
http://www.w3.org/TR/xml11/#NT-Name

The colon (:) is given as valid character.

Am i misunderstanding something?

Thanks,
Friedrich Röhrs