cross-platform backup tool Strange string of messages; rdiff-backup won't run

I just tried to run rdiff-backup on my Ubuntu 20.04 setup on a Dell XPS 
13". The following command has run successfully any number of times in 
the three months since I got my new box (Dell factory Ubuntu image 
installed.) Now I get this strange string of messages. What do they mean?

eric@eric-XPS-9315:~$ sudo rdiff-backup  --exclude 
"/home/eric/VirtualBox VMs" --include /home/ --include /var/www 
--include /usr/share/fonts --exclude '**' / 
/media/eric/021cc172-036d-4b8c-be87-c6298c9f7c4c/XPS-2022-08
[sudo] password for eric:
Traceback (most recent call last):
   File "/usr/bin/rdiff-backup", line 19, in <module>
     import rdiff_backup.Main
   File "/usr/lib/python3/dist-packages/rdiff_backup/Main.py", line 30, 
in <module>
     from . import (
   File "/usr/lib/python3/dist-packages/rdiff_backup/SetConnections.py", 
line 31, in <module>
     from . import Globals, connection, rpath
   File "<frozen importlib._bootstrap>", line 991, in _find_and_load
   File "<frozen importlib._bootstrap>", line 975, in 
_find_and_load_unlocked
   File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
   File "<frozen importlib._bootstrap_external>", line 844, in exec_module
   File "<frozen importlib._bootstrap_external>", line 976, in get_code
   File "<frozen importlib._bootstrap_external>", line 640, in 
_compile_bytecode
ValueError: bad marshal data (unknown type code)

-- 
Eric Beversluis www.ericbeversluis.com Forthcoming: /For Love of a Father/