The above message is shown when logging into a database that is shared and has sync enabled on ver 16.
Version Found: 16.0
In shared database environments with sync turned on you may receive Error: "The path is not of a legal form" after login.
This issue was resolved with the release of Hotfix 2 for Act! v16. You can download this hotfix from our Download Center:
North American versions: http://act.com/support/download-center/
International English versions: https://www.act.com/en-uk/resources/downloads
Status: Closed, fixed in v16 hotfix 2