Problem - reindex Magento 1.9.3

[kogutu]

Hello, I have problem, I try reindex integra_solr.

Problem: I try reindex integra_solr, when I run php shell/indexer.php -reindex integernet_solr I get this error: Mage registry key "_singleton/integernet_solrobserver/observer" already exists

I run, delete, clear compile, flush all cache, turn on/off extension but still i get this same problem.