Are you trying to login as the local administrator? If so, did you activate the account? By default, the local administrator account is disabled and needs to be enabled. The TechNet article ‘Enable and Disable the Built-in Administrator Account’ shows you how.
Are you using the SLSHARE setting in your deployment share rules to collect the log files from the deployment? The help files in MDT show you how to set this. Basically, create a folder in your deployment share named ‘Logs’ and then in your deployment share rules, add the SLSHARE setting:
SLSHARE=\Server\Deploymentshare$\Logs
Once this is done, all the log files will be uploaded to your deployment share for each deployment to help you with troubleshooting issues with your deployments.
Hope this helps,