Your site was unable to contact Apache Solr server I have both Apache Solr Search and Search API modules installed on drupal 7.  I have installed SolrPhpClient version r22 (that was recommended in a site vs. r60) in sites/all/libraries/libraries folder. 

When I place XML files from Apache Solr Search on Solr Server, Search API would not index. When I place XML files from Search API on the server, Search API seems to work fine but I get Your site was unable to contact Apache Solr server error message on Status Report. In this case I can see mysite:8983/solr/admin but when I click on PING button it shows 500 error message.

Is this supposed to be this way? Can I trust the Search API working fine (is the error message pertained to Apache Solr Search not having its XMLs on server and can be ignored)? Any suggestions to fix this?

Any help would be greatly aprectiated and let me know if you need more info.

Thanks alot.
Some days ago I had a similar problem.

I've download the SolrPhpClient in the .zip file and Search API was not able to connect to the Solr Server (I don't know Apachesolr, I don't use it).

But if I download the .tgz version of the client.. it works. I think that in the .zip version there is some problem with permissions.

So: if you've download the .zip version, try the .tgz.

And obviously try also the r60 version, I use it alwyas.