I tried to upload album using the full RSS code, the RSS link, and just the Album number listed in the RSS feed. None of them would upload the album.
From the look of things this should be a great plug-in for use for Picasa/Google+. Now that they are dumping the Picasa name and just having it integrated into your + account it might be time to revisit how the plug-in functions.
For the author I am just now dipping my toes into PHP so this is beyond my skill level but for us users I want to thank you for your work it is very appreciated.