SF SFTP - Unsupported Operation Exception - Key Based Authentication In PI

Hi All,

Before I have used User name password based Authentication in SAP PI receiver SFTp channel.

At that time is it is worked.

But now I have changed the configuration, like i have changed the configuration to Key based Authentication in SFTP receiver channel.

I have saved SAP PI SFTP public keys in SFTP folder as mentioned in the below link. under 4.2 section.

http://a248.g.akamai.net/n/248/420835/c78565d64f774a8543b33e40855a31201438e31bca9927abbd3e0ff1e993eff4/sapasset.download…

But now i am getting error like Unsupported Operation Exception in RWB.

PLease find the below screen shot. Please help me to resolve the issue...