Here is the description from the ANT build script:

      [sql] Failed to execute: /* add an index on most of the observation_fact fields */ CREATE INDEX OF_IDX_ALLObservation_Fact ON Observation_Fact ( Encounter_Num , Patient_Num , Concept_Cd , Start_Date , Provider_Id , Modifier_Cd , inst
ance_num, ValType_Cd , TVal_Char , NVal_Num , ValueFlag_Cd , Quantity_Num , Units_Cd , End_Date , Location_Cd , Confidence_Num , Sourcesystem_Cd ) [sql] com.microsoft.sqlserver.jdbc.SQLServerException: The index 'OF_IDX_A
LLObservation_Fact' on table 'Observation_Fact' has 17 column names in index key list. The maximum limit for index or statistics key column list is 16.