Hello,
You need to check the BAdIs: in most cases, there was either some BAdI that was activated but not implemented, or present, but inactive.
So check this information in your system and see whether this may be also your case. If you don't need the BAdI, please deactivate it through transaction SE18.
Please pay special attention to "\CLASS=CL_IM_SIC_NOTIFY_ILN", where is it defined.
Regards,
David