Category: Opensolr and Drupal
First, you need to learn how to get started with your opensolr index for drupal.
Now, once you've uploaded your drupal configuration files in your opensolr index, you should make sure that all the requestHandlers inside the solrconfig.xml file, will have the preceding slash at the begining of it's name.
Make sure you do the same for all other requestHandler tag in your solrconfig.xml file. Otherwise drupal will keep saying it can't find your opensolr server.
Another known issue is described here.
If you still have issues, please Contact Support