running drdoogie last night and got this error when it came time to vote

{:error_perser_exception=>#<NoMethodError: undefined method `[]' for nil:NilClass>, :original_response=>{"jsonrpc"=>"2.0", "error"=>{"code"=>-32003, "message"=>"Unable to acquire database lock"}, "id"=>280}}

Also with the max-age of the post, isnt it best to set it between 30-60 to maximize profits on the upvote .. I'm just a plankton but I notice some accounts like @steiller seem to be using a curation trail bot and making consistent SP ...