As the error messages state, you need a Spatially indexed column to make use of the Spatial operators.
You can get equivalent functionality from the RELATE
function in the SDO_GEOM
package using the mask "ANYINTERACT":
SELECT sdo_geom.relate(a, 'ANYINTERACT', b, 0.05)
FROM dual
http://docs.oracle.com/cd/B19306_01/appdev.102/b14255/sdo_objgeom.htm#BGHCDIDG