BUG #15330: Can't restore backup file

The following bug has been logged on the website:

Bug reference: 15330
Logged by: João Vitor Cardoso
Email address: joaovitorcardoso.cdc@gmail.com
PostgreSQL version: 9.6.9
Operating system: Win10
Description:

Ever since I started using PG 9.6, I've never been able to restore a
database with a backup file.
There is always the same error when I try (and I've tried in all sorts of
ways): "object of type 'bool' has no len()"

My database has Blobs, one-to-may relationships, etc.
All I can think about (that may be causing this error) is my encoding. I use
WIN1252 (I'm brazilian, therefore I speak portuguese and need special
characters like ã, à, é, í... - and I'm sorry if I made any mistake in this
text).

I used PG 9, 9.1 and 9.2 and trully expected a better expercience in these
new versions but I'm getting really frustrated. #DontAbandonPGAdminIII

If you provided me with an e-mail address I could give you the server
address, backup file, all you may need. Just help me, please.

P. s.:
Yes, I tried:
- Rebooting,
- Updating,
- Cleaning the target server (reinstalled the postgresql server),
- Making the backup process as Tar, Custom, Directory, Plain...
But nothing seems to work.

Here is the log:
------------------------------------------------------------------------------------------------------------------------
2018-08-15 21:49:39,550: ERROR werkzeug: Error on request:
Traceback (most recent call last):
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\werkzeug\serving.py", line 270, in run_wsgi
execute(self.server.app)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\werkzeug\serving.py", line 258, in execute
application_iter = app(environ, start_response)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1997, in __call__
return self.wsgi_app(environ, start_response)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1985, in wsgi_app
response = self.handle_exception(e)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1540, in handle_exception
reraise(exc_type, exc_value, tb)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\_compat.py", line 33, in reraise
raise value
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1982, in wsgi_app
response = self.full_dispatch_request()
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1614, in
full_dispatch_request
rv = self.handle_user_exception(e)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1517, in
handle_user_exception
reraise(exc_type, exc_value, tb)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\_compat.py", line 33, in reraise
raise value
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1612, in
full_dispatch_request
rv = self.dispatch_request()
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1598, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask_login.py", line 792, in decorated_view
return func(*args, **kwargs)
File "C:\Program Files (x86)\pgAdmin
4\v3\web\pgadmin\misc\bgprocess\__init__.py", line 62, in index
return make_response(response=BatchProcess.list())
File "C:\Program Files (x86)\pgAdmin
4\v3\web\pgadmin\misc\bgprocess\processes.py", line 571, in list
IS_PY2 and hasattr(p.desc, 'encode') else loads(p.desc)
TypeError: a bytes-like object is required, not 'str'
2018-08-15 21:50:16,994: ERROR werkzeug: Error on request:
Traceback (most recent call last):
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\werkzeug\serving.py", line 270, in run_wsgi
execute(self.server.app)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\werkzeug\serving.py", line 258, in execute
application_iter = app(environ, start_response)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1997, in __call__
return self.wsgi_app(environ, start_response)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1985, in wsgi_app
response = self.handle_exception(e)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1540, in handle_exception
reraise(exc_type, exc_value, tb)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\_compat.py", line 33, in reraise
raise value
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1982, in wsgi_app
response = self.full_dispatch_request()
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1614, in
full_dispatch_request
rv = self.handle_user_exception(e)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1517, in
handle_user_exception
reraise(exc_type, exc_value, tb)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\_compat.py", line 33, in reraise
raise value
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1612, in
full_dispatch_request
rv = self.dispatch_request()
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask\app.py", line 1598, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "C:\Program Files (x86)\pgAdmin
4\v3\venv\Lib\site-packages\flask_login.py", line 792, in decorated_view
return func(*args, **kwargs)
File "C:\Program Files (x86)\pgAdmin
4\v3\web\pgadmin\misc\bgprocess\__init__.py", line 62, in index
return make_response(response=BatchProcess.list())
File "C:\Program Files (x86)\pgAdmin
4\v3\web\pgadmin\misc\bgprocess\processes.py", line 571, in list
IS_PY2 and hasattr(p.desc, 'encode') else loads(p.desc)
TypeError: a bytes-like object is required, not 'str'
2018-08-15 21:55:16,582: ERROR pgadmin: object of type 'bool' has no len()