ReadyNAS NV+ V2 Permissions

I recently purchased the ReadyNAS NV+ V2 RND4000 device. My primary use of the device is to use as a backup device for the PCs that I have. For backing up I use EMC Retrospect and I am running it from a PC which is Windows 7 64-bit. After purchasing the device and setting up the share to use for my backups I performed my initial backups (and duplicate's) to the share. It all ran without a hitch but it took FOREVER to generate the backups. Somthing has now changed and everytime I attempt to run a backup it ends and Retrospect is telling me "insufficient permissions" for everything it is trying to write. Can someone tell me what my issue might be or give me some assistance in resolving?

More information: I have also mounted all of my shares as a mapped network drive to my PC. I can get to the shares for both read and write access from the mapped drives. It is just Retrospect that is failing when trying to write.