The error is usually due to a conflict of phase and material named objects in the CCL. Potentially, the problem may be specifically related to using the same name for a material in one domain and a Fluid or Solid Definition in another. This conflict may not produce any warning messages in CFX-Pre, and may not cause any problems in the CFX-Solver until the name is used in an expression for a parameter which the CFX-Solver must evaluate (e.g. a source). Ensure that if there is a material with the same name as a fluid/solid definition, it is only referenced by that particular fluid/solid definition.