AFP Permission issues after new FW update

I believe that I'm seeing the same issue that other folks are seeing. After upgrading from 4.2.17 to 4.2.18 on my Ultra 6, I can't write to the shares that I used to be able to write to under the previous firmware after connecting with my normal username. I tried creating a new share, a new group, and playing around with the options in the Advanced tab in the share list, but I still can't write files. The user/group and permissions on the ReadyNAS haven't changed for the share or any of the directories in it, and I can connect just fine - I just can't write.

I *can* write to those same shares if I connect to the share as "guest". The files get different permissions when I do that, but my issues with writing seem to be limited to connections made with my real username. After connecting to the same shares using CIFS using my real username, I can also write just fine. So, problems with AFP only when connecting with a real username.

I see the same behavior from a MBP running 10.6.8, and an iMac running 10.7.

The failures in the netatalk log are the ones mentioned above:

47.131916 afpd[7621] {acls.c:1121} (E:Default): getnamefromuuid(uuid, &username, &uuidtype) failed: Resource temporarily unavailable

Rob