Actually, there is already a sitemap or quasi-sitemap generated by blogger. You can see it in you robots.txt file [ahem, ht*p://yoururl.blogspot.com/robots.txt] This site map is read by any spider that bothers with the map. There is no point in adding the new sitemap to Google Webmasters as it is already there. If you need the sitemap for other reasons - use atom.xml
I have www. in the url. " www.my-discus-fish.blogspot.com ". I have 2 doubtfull palces 01. Both atom.xml and rss.xml redirect to http://feeds.feedburner.com/MyDiscusFish So this might be the problem ? 02. Problem might be the urls ? for example http://my-discus-fish.blogspot.com/2008/12/discus-are-having-hole-in-head-disease.html ?
I suggest you to use your blog atom and if you have more than 100 pages then the code will bit different, same if you have more than 200 then it changes and similarly if you have more than 300 then also changes.... so go on like this... just put your blog url in webmaster tool and they will provide you a code you have to put it in your blogger edit HTML area and then click on verify button in webmaster tools button... they will verify it nd will just say you to wait for some time. So simple