Cannot do Solr searching because of disabling replication

I try to do Solr searching but I cannot. Solr give me the error message:

Update failed, could not disable replication for 'core name_en' - Request to http://:3000/core/core name_en/replication%2Fupdate failed - 500 Internal Server Error

I try to comment the replication on solrconfig.xml but it's ok for a first few times but the problem is come back again.

I try to disable replication by running this command on the browser: http://:3000/core/core name_en//replication?command=disablereplication

but I got HTTP 404

Where should I fix it? Solr slave server?