do you have a jetty install of solr downloaded (or does this come with acts_as_solr - can’t believe this)? Have you got java in your path? What is “java -version” on the command line giving you?
First we need to know if you match the prerequisites. Especially java and solr up and running. Do things step by step! Get information on the solr site (google:solr) and maybe run their example before you integrate solr into ruby and rails by using acts_as_solr. I’ve tried it some time ago and had no problems either. But I’m coming from java land and ymmv.