x-sname field indicates the stream name. I feel you're checking the wrong colum.
You can find the details of other access log fields here : http://livedocs.adobe.com/flashmediaserver/3.0/docs/help.html?content=05_logs_09.html
access.00.log indicates the newest access log, with access.01.log being older than 00, access.02.log being older than 01 and so on.
Hope this helps.