Resolution:
After changing the HTTP port of a WebLogic installation, you will need to change the value in the GridServer configuration as well so that the Manager reports the correct port. There is currently no way to do this via the GridServer Administration Tool, so the following edit must be made:

In the following files, change the noted values to reflect the new Manager port:

In livecluster/WEB-INF/config/installation.properties, change:

    * DSBaseUrl
    * DSWebappUrl
    * DSPrimaryDirectorHttpPort

In livecluster/WEB-INF/config/driver.properties, change:

    * DSWebserverPort
    * DSWebserverBaseUrl