Not able to drop application

alter Application ${cube_data_base_name}DP disable connects

alter system kill request on application ${cube_data_base_name}DP

alter system logout session on application ${cube_data_base_name}DP

alter system unload application ${cube_data_base_name}DP

drop Application ${cube_data_base_name}DP cascade force

After all his, the drop application command still fails and the only way I can make it work is to kill the process ID associated with the application. Any suggestions on how I can resolve this issue? Any other commands that might release all the locks and allow me to drop the application?