Elasticsearch-river-couchdb remote db indexing error

Elastic Stack Elasticsearch
1

Hi, I have a couchdb installed and up and running and i want to have a search engine in different machine.
so i installed elasticsearch and elasticsearch-river / elasticsearch-head plugins in a different machine. (this new machine doesn't have a couchdb)

and i send a curl something like this,

url : http://localhost:9200/_river/remote_db/_meta

{
"type" : "couchdb",
"couchdb" : {
"host" : "192.168.1.100",
"port" : 80,
"db" : "remote_db",
"filter" : null
},
"index" : {
"index" : "remote_db",
"type" : "remote_db",
"bulk_size" : "100",
"bulk_timeout" : "10ms"
}
}

and i found this elasticsearch-head , browser section
_index _type _id _score error
_river inventory _status 1 NoClassSettingsException[Failed to load class with value [couchdb]]; nested: ClassNotFoundException[couchdb];

any idea?