We can't provide support for third-party actions, but we've seen similar behavior with other actions that access C$. Due to a quirk in Windows, the local C$ will be opened in some cases, if you do not have access to the target machine's C$. One would expect an access denied error instead.
Keep in mind that actions are run in the security context of the user initiating the action, so the user initiating the action must have access to C$ on the target computer. You can use
runas.exe to run an action as a different user.
