Hi Deepak,
Using PFAC transaction use a Rule Function Module to dynamically pick the entries from that database table. It seems that e-mail agent wasn't defined correctly , may be agent determination was failing in the e-mail step. Make use of Rule F.M.
You also mentioned that the e-mail should be sent to notification creator. If that's the case you can make use of WF_INITIATOR expression in the e-mail step itself.
Regards,
Lakshman