Very happy to help! First round, not so good.
The site doesn't crash, which is a good thing. However...
Internally, all of the formatting disappears on the TubePress Options page. All settings are on one page, and the niceties like the color pickers, etc. are gone. (Debugging is turned on.)
Externally, you get this:
Fatal error: Can't inherit abstract function tubepress_lib_api_streams_StreamInterface::close() (previously declared abstract in puzzle_stream_StreamInterface) in /(path)/wp-content/plugins/tubepress_4_0_0_RC1/src/add-ons/core/classes/tubepress/lib/impl/streams/puzzle/FlexibleStream.php on line 15
See here:
http://testground.cr...t/tube4/videos/
This is a playlist that works in TubePress 3. See here:
http://testground.cr...t/divine/video/