This message is displayed when LoadComplete fails to locate plugin information in the plugin file. Typically this happens for one of the following reasons:
The plugin file is corrupted.
The plugin is not supported by the LoadComplete edition which you have. For instance, you are trying to install a plugin from another SmartBear product into LoadComplete.
The major version of the plugin does not match the major version of LoadComplete. Only those plugins that have the same major version number as LoadComplete are permitted to be installed.