Is Z: a mapped drive (mapped to a network location), or an additional local drive?
If the later then that should work, provided that the content folder exists in the root of drive Z:
If this is a mapped drive then you need to ensure that the drive is accessible without having to enter
a username and password. If that still doesn’t help, see if you can use the UNC path instead, like
this:
<StorageDir>\\servername\sharename\content</StorageDir>
or similar.
If still no luck, then post the related errors seen in the error log: [install-dir]/logs/wowzamediaserver_error.log
Daren