"buitlin"? Is is a typo while copying the error message?

The warnings are normal, these theme elements were added later. They
will disappear when you save the theme again.

Now, idle starts another process to interpret the commands, and use
sockets to communicate between them. You may have a firewall problem.

Can you try to run idle.py with the "-n" option? This does not create a
subprocess, all commands are run in the main process.