Exception CX_CRM_ICI_EXCEPTION. What does it mean?

Hello,

I have a problem, I am doing the integration between CRM and CTI with the help of TestFrameWork.

Using the method "listen" of the class "CL_BCB_PHONE_CALL" I returned an exception. Exception CX_CRM_ICI_EXCEPTION. Why? What does it mean?

code:

data: PHONE_CALL Type Ref To CL_BCB_PHONE_CALL

LOOP AT item_refs ASSIGNING <i>.

phone_call ?= <i>-item_ref.

phone_call->listen( supervisor_phone_line2 ).

ENDLOOP.