From the Vault SDK Documentation, error 1058 indicates that an attempt was made to add a file with the same name as a file already existing in the Vault (and the option to require unique file names is turned on). So presumably Thunderdome is attempting to add a file with the same as one that already exists in the Vault elsewhere. One solution is to turn off the "Require Unique filename" option (Tools->Administration->Vault Settings->Files->Enforce Unique File Names)
I ended up deleting the existing Deployment.td file, and upon doing so i was able to create my new Deployment. I'm guessing the Deployment file, either became corrupt or was put into a read only state upon which ThunderDome could not write new deployments to it.
