Encounter ilm flow for a toplevel design

Hai

I am running a hierarchical design with a block level which is integrated into a top level

i created a ilm directory in the encounter session of the block level by using the command

createInterfaceLogic -dir xxxx

then with this dir i started a new encounter session and laoded the ilm directory in the conf file of the top level then

specifyIlm -cell xxxx -dir yyy/xxx

flattenIlm

when i run this command i could not flatten the design to run timeDesign its showing the following error

**ERROR: (ENCILM-281): There is no netlist associated with the intended ILM specification for cell: xxxx
**ERROR: (ENCILM-289): No ILM will be created for cell xxxx.
**ERROR: (ENCILM-290): The specification may be from the command 'specifyIlm', GUI, or loading design config file saved from previous 'saveDesign'.


why this is happening what must be done to overcome this error


Plz help me

Thank you......