Unfortunately, that didn't fix it. The rbfeeder log shows:
Can't connect to 978 source (127.0.0.1:28380)
I'm using Dump1090 instead of Dump978, but that may not be relevant. I configured rbfeeder to listen on port 30005.
The 'sudo rbfeeder status' command shows:
Error opening the listening port 32458 (Raw TCP output): bind: Address already in use
So I'm out ideas.