Fixed Value Attribute will not accept values from query. Why won't eB save the text value returned from a SQL query into the attribute?

Fixed Value Attribute will not accept values from query.

Why won't eB save the text value returned from a SQL query into the attribute?

The attribute is set up as a Fixed Value attribute which should allow entry of alpha-numerics up to 255 characters.  The query is: SELECT FULL_NAMES NAME FROM PERSONS WHERE STATUS = 'A' and returns what is expected to the 'Current Values' list when tested.

When attempting to populate this attribute on a document, the following error is returned: 'Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index'

Any ideas?