[LAD] Running SLV2

Hello, I've installed the slv2 package on my machine but can't run any plugins? When I start lv2_jack_host get lots of known plugins URI's like http://ll-plugins.nongnu.org/lv2/dev/klaviatur/0.0.0 which I want to run. But when I start I get lv2_jack_host http://ll-plugins.nongnu.org/lv2/dev/klaviatur/0.0.0 Failed to find plugin http://ll-plugins.nongnu.org/lv2/dev/klaviatur/0.0.0. also running it with lv2_jack_host /usr/lib/lv2/klaviatur.lv2/manifest.ttl URI: /usr/lib/lv2/klaviatur.lv2/manifest.ttl Failed to find plugin /usr/lib/lv2/klaviatur.lv2/manifest.ttl. or lv2_jack_host file://usr/lib/lv2/klaviatur.lv2/manifest.ttl URI: file://usr/lib/lv2/klaviatur.lv2/manifest.ttl Failed to find plugin file://usr/lib/lv2/klaviatur.lv2/manifest.ttl. fails. Can anybody give me a hint how to start this host with the correct URI parameter? Thanks Chris