You can do this from your computer. This is what I did:
(1) Create a new repository in unfuddle (e.g., digsite)
(2) Open the command line and run:
svnsync init --username hugo http://hugo.unfuddle.com/svn/hugo_digsite https://mwork.nabble.com/svn/rep/trunk/digsite
svnsync sync --username hugo http://hugo.unfuddle.com/svn/hugo_digsite
You have to replace my name with your unfuddle login in the URLs above. It is going to ask you the passwords, so you have to enter them for unfuddle and for nabble's repository.
Please note: It will go through ALL revisions in the Nabble repository, one by one, skipping those that don't match the path. Each revision takes 2 seconds to finish, so the entire process takes ~6 HOURS to finish. I didn't run it till the end, but I assume this will work. You can try it.