New user... can't get a map/campaign to load

[Gamers Path]

Some assistance please. I'm a brand new user. Downloaded rptools recently and just started playing with it a few days ago. I created just a small map that I was planning on using as a trial run to get familiar with things. But now I cannot load it. I've tried creating a couple others and I can't load those also. The message that pops up says the campaign file is not readable by this version... message: Cannot construct sun.awt.geom.Order0 as it does not have a no-args constructor.
I downloaded the current version a month ago maybe... and have used no other versions.
Thanks for any help!