Defining enumeration attributes for DITA topics - error on checking in.

I defined my ditabase bursting as follows:

<dmsmetadata>
<metadatarule sourcetype="text" elementname="concept" expr="prolog/metadata/category" metadata="com.terrestrialenergy.DITAcategory"/>
<metadatarule sourcetype="text" elementname="topic" expr="prolog/metadata/category" metadata="com.terrestrialenergy.DITAcategory"/>
<metadatarule sourcetype="text" elementname="reference" expr="prolog/metadata/category" metadata="com.terrestrialenergy.DITAcategory"/>
<metadatarule sourcetype="text" elementname="task" expr="prolog/metadata/category" metadata="com.terrestrialenergy.DITAcategory"/>

On the site utilities/Type and Attribute Management,

1. I defined my DITAtopic as an EPM document subtype.
2. I added the attribute DITAcategory to the DITAtopic subtype..
3. I added the constraint of my DITA topic enumeration to the DITAcategory attribute.
4. I made sure all my DITA topics had the correct category='REG".  

 <prolog><metadata><category>REG</category></metadata></prolog>​

• When I tried to load my bookmap, none of the child topics were loaded.

The error message:

Checkin Failed
Number of conflicts found:3
:Attribute com.terrestrialenergy.DITAcategory has values that violate the attribute constraints. "You must enter a value for DITA Document Category.". The values must be modified before checking in.
:Attribute com.terrestrialenergy.DITAcategory has values that violate the attribute constraints. "The value for attribute DITA Document Category must be one of the following: REG. The pre-existing value may no longer be valid for this attribute.". The values must be modified before checking in.
:Attribute com.terrestrialenergy.DITAcategory has values that violate the attribute constraints. "You must enter a value for DITA Document Category.". The values must be modified before checking in.