Per your explanation of column names changing the statement as seen below resolves the issue.

UPDATE tl_2008_us_state

SET BoundaryGeog = GEOGRAPHY::STGeomFromWKB(Geom.MakeValid().STAsBinary(), 4326)

WHERE NAME NOT IN('Massachusetts', 'New Mexico', 'Wyoming', 'Montana', 'Texas', 'North Carolina', 'Arizona', 'Tennessee', 'Utah')