Hi Alex,

the robots.txt is not involved in the xls file permissions.
Maybe the htaccess can be responsible, i'm not a great expert of htaccess, i see the following rules that states a rewrite rule for xls files, maybe that could be the problem:

Code:

RewriteRule ^administrator/(components|modules|templates|images|plugins)/.*\ .(jpe|jpg|jpeg|jp2|jpe2|png|gif|bmp|css|js|swf|html|mpg|mp3|mpeg|mp4|avi|wav|ogg|ogv|xls|xlsx|doc|docx|ppt|pptx|zip|rar|pdf|xps|txt|7z|svg|odt|ods|odp|flv|mov|htm|ttf|woff|eot|JPG|JPEG|PNG|GIF|CSS|JS|TTF|WOFF|EOT)$ - [L] RewriteRule ^administrator/ - [F] ## Allow limited access for certain Joomla! system directories with client-accessible content RewriteRule ^(components|modules|templates|images|plugins|media|libraries|media/jui/fonts)/.*\ .(jpe|jpg|jpeg|jp2|jpe2|png|gif|bmp|css|js|swf|html|mpg|mp3|mpeg|mp4|avi|wav|ogg|ogv|xls|xlsx|doc|docx|ppt|pptx|zip|rar|pdf|xps|txt|7z|svg|odt|ods|odp|flv|mov|ico|htm|ttf|woff|eot|JPG|JPEG|PNG|GIF|CSS|JS|TTF|WOFF|EOT)$ - [L]

Finally, about the mobile sitemap if you want to submit it notice that by default it's empty. Opening every data source in edit mode you can enable inclusion of contentns in the mobile sitemap, this is done because you should publish in the mobile sitemap only the contents suitable for mobile.