CouchDB replication is broken: Server responds "function_clause" error

This affects users that are new to UbuntuOne (my main account is not affected, but the test one just created is).

'{"error":"unknown_error","reason":"function_clause"}\n' is returned to the clients that try to access the server.

This is accompanied by
[Fri, 19 Mar 2010 22:20:02 GMT] [error] [<0.5487.24>] function_clause error in HTTP request
in couch.log (@beautyberry).

This may be not related but I decided to inform about this just in case:
At the same time there are some strange (for me) exceptions in ini_apply_changes.log:
raceback (most recent call last):
  File "/srv/couchdb/scripts/ini_apply_changes.py", line 263, in <module>
    claim_changes_file_and_apply_to_ini(changes_file_name, ini_file_name)
  File "/srv/couchdb/scripts/ini_apply_changes.py", line 148, in claim_changes_file_and_apply_to_ini
    assert os.path.isfile(orig_changes_file_name), "changes must be a file"
AssertionError: changes must be a file