Unable to clone File Adapter receiver channel for parallel processing

Hi Experts,

I am using variable substitution for File - RFC - File with out BPM scenario(using request response, oneway bean).

While i placed the file in the sender FTP folder, the file didnt get picked up, but in communication channel monitoring, i am getting error ' Unable to clone File Adapter receiver channel for parallel processing'.

Can anybody provide me suggestions to solve this error.

Note : without variable substitution , the interface is working good.

Is it due to, i am trying the source structure field in response file adapter?