error with stratixIII cell

Hi All

I was working on a design where i instantiated the stratixIII cell in a smaller entity and compiled the small entity as a top module and the process completed successfully.

Then i instantiated this small entity in another top entity and compiled the process completed also successfully

Let's sat i have this hierarchy

small_entity inside Top1 and Top1 is inside Top2

small entity compiled successfully

Top1 also compiled successfully

but when i compiled Top2 this error appears

Error: cout and shareout ports of atom "\Cell_instantsU1:15:fa" must feed the same atom

Am using QuartusII , StratixIII device

Thanks in advance

Amr