Jessica,
It seems you are trying to publish a service to your GIS Server. When you say you are using the World Street Map, can you be more specific? Are you trying to reference a map service inside your MXD, then trying to publish this to your GIS server? If you are, ArcGIS Server doesn't support this.
Also, you might check the log files on your GIS server to see if there is any additional information. (ArcGIS Server Manager lets you look at the log files.)
Thanks,
Mike