Deployments are failing on machines that are configured, under a deployment template, to download patches directly from a Distribution Server rather than a console push. The error in the st.distribution servers.log shows the following:
08:39:02 Distribution Servers
File cannot be copied from this location.
The scheduler credentials are corrupt or invalid.
Uninstall and Reinstall the Scheduler on the affected machine using instructions found at How To: Uninstall & Reinstall The Shavlik (ST) Remote Scheduler Service On A Single Machine to refresh the credentials file.