Go to the ftp root (download.simplemining.net) and you will see all available versions there. The dag fix version is labelled a little differently from the link so the link is broken.
Now there's two versions that have dagfix in their name :
http://download.simplemining.net/simpleminer-RX-v1118-17.30-dagfix.img.zip (updated 13th Sept)
http://download.simplemining.net/simpleminer-RX-v1118_dagfix_computekernel.img.zip (updated 1st Sept)