As per that "Remote Execution driving me insane" thread. The remote process "appears" to be running with your WMI credentials (eg, if you look in XP taskmgr on remote machine, your accountid is attached to the process). But, because of some limitations with NTLM challenge response - the process on the remote machine DOES NOT really have full network rights. If you need to access a remote share - have to map it with username & password supplied.

From reading the literature. This is an basic Windows NT problem, and affects not just WMI, but other things such as remote TELNET sessions.

My two cents. Sorry if not much help in furthering the cause. Might want to inverstigate further.