Changing MEP duct properties via lisp eg LiningThickness and Insulation

[Anonymous]

Hello,

Please does somebody know why the following lisp retuns an error "lisp value has no coercion to VARIANT with this type:"

It really should work. Select a MEP duct.

(setq obje (vlax-ename->vla-object (car (entsel))))
(vlax-put-property obje 'InsulationThickness 0)

or even this gets the property - which it does OK and then try to set it to the same.

(setq lith (vlax-get-property obje 'LiningThickness))
(vlax-put-property obje 'InsulationThickness lith)

Thanks in advance
David