I am not sure if Capture CIS schematics can be translated to Concept HDL. There are no translators available on the web. However, you can get if you are a CADENCE customer, then, the customer support has the necessary translators to do the job for you. As such the translators are not available for free download or provided as a part of the cadence suite of tools.
I am not sure about what error it gives.
But I read about converting SCALD to new concept hdl it is BIG process I d’nt know about orcad to concept hdl.