When installing the ArcGIS Web Adaptor (IIS) on non-English Windows 2003 systems, the Network Service account is not given read/write permissions on the C:\inetpub\wwwroot\arcgis\webadaptor.config file.
Manually grant localized network service account read/write permissions to <a href="file:C:/inetpub/wwwroot/arcgis/webadaptor.config." target="_blank">C:\inetpub\wwwroot\arcgis\webadaptor.config.</a>