When installing the pyload package and running setup-pyLoad from the shell. If you accept the defaults for the web interface pyload is installed on port 8000
Quickbox by default is set to try and open the pyload link as https://webserveraddress/pyload/login
When this happens links to stylesheets and image are wrong as they are called from /pyload/pyload
The workaround is to manually go and edit the path for the pyload link found in
Either explain this to the user when the package is install or dynamically update config.php so it knows the correct address and port that pyload is listening on.
Quickbox is great so much work has gone in to it but the pyload integration just needs a little more polish.