This error occurs when an attempt is made to explicitly load an IC whose applications are already present in the development image. The IC load operation attempts to load the classes into the namespace associated with the Application where they are defined. Since those classes already exist in the Application namespace and are marked as read-only by the Application that holds onto them, any attempt to load the duplicate objects fails.

In order to avoid this situation, you must first unload the code from the development image prior to performing the explicit load of the IC.