You have entered an incorrect URL format. SuperContainer URLs should start with the host and application name, then the action type, then the resource identifier. For example:
http://localhost:8020/SuperContainer/Files/unique/resource/identifier
In the above example the host and application name are http://localhost:8020/SuperContainer
The resource identifier is /unique/resource/identifier (this can be any arbitrary reource names joined by slashes).
The bold portion (Files) is the action type. Action type must be one of the following:
Other valid urls are for the Index and Registration pages.
Important: older versions of SuperContainer used a different URL syntax. Please upgrade your FileMaker solutions accordingly.
Please consult the SuperContainer documentation for more on what the different action types are used for.