I had the same problem…using the basic uploader I got the error:
Error saving media attachment.
Using the flash uploader, I got an error about file permissions on the server.
I tried deleting the uploads folder, changing permissions to 777, 755 etc etc. But nothing helped
My fix: I unchecked the “Organize my uploads into month- and year-based folders” checkbox in /wp-admin/options-misc.php and that seems to work.
I would like to get in touch with Jamie and the other developers working on Gengo. http://jamietalbot.com/ is down, so I am having difficulty trawling the web to find contact details for anyone. Please contact me because I would like to contribute to the project.