The gatecrash set is not downloading.
I did a quick check and there seems to be an inconsistency between the Medium quality and the High quality versions of the Magic plugin.
Therefore; you're probably using the Medium quality version plugin, try using the High quality version: http://www.siegescg.com/magicthegathering/high/updatelist.txt
I don't know why one isn't fully updated...
both medium and high seem to be working now for gatecrash at least. still not working for you?