Great extension, but .... unfortunately the 'badlogin' feature depends on the use of memcache. Most likely a good idea for larger installations, but makes this feature useless for most web-hosted installations that do not provide memcache.
This problem has been reported as a bug on Bugzilla - to me it looks to be a feature, though.
Is there a chance that anyone rewrites the code to make use of database cache as an option? (I myself just don't know enough about this.)