Get the defaults back from a fresh download of sepefeet's silverfish.
Completely remove silverfish from your externbot folder in hearthranger and copy it from your new download.
Test it from the settings menu, see which ai bots are available.

Default settings should work good with minion focused decks, some spells are harder for the bot to use correctly.
Just include plain, damage dealing spells and you will be alright I think.

For better optimised decks look at
http://www.hearthranger....deck-you-can-build.aspx
If you haven't.