This error appears for Consolidation job.
It means that the mentioned source agents are configured to consolidate the files into one destination folder. Consolidation job is designed in a way that all source agents are uploading their files into their own designated subfolder on destination server and do not exchange data with each other. This is achieved by using %SRC:AGENT_NAME% tag in destination path. If this tag is removed from path, the error pops up.
To fix it go to edit the job, at step "Destination agents' add %SRC:AGENT_NAME% tag into the path so that looks like this:
C:\Users\Public\Documents\Resilio Connect Agent\Consolidation Job\
Surely, you can have your preferred location instead of C:\Users\Public\Documents\Resilio Connect Agent\Consolidation Job\