Query Plugin needs a jar file

When using the query plugin it fails because a dependency jar of jackrabbit is missing (http://www.slf4j.org/ )

Error number 4001 in 4: Error while parsing velocity page Test.QueryTest Wrapped Exception: Invocation of method 'search' in class com.xpn.xwiki.api.XWiki threw exception java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory @ Test.QueryTest44,21?

java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
at org.apache.jackrabbit.core.query.QueryTreeBuilderRegistry.<clinit>(QueryTreeBuilderRegistry.java:40)
at org.apache.jackrabbit.core.query.QueryParser.parse(QueryParser.java:53)
at com.xpn.xwiki.plugin.query.QueryPlugin.parse(QueryPlugin.java:90)
at com.xpn.xwiki.plugin.query.QueryPlugin.xpath(QueryPlugin.java:100)
at com.xpn.xwiki.plugin.query.QueryPlugin.search(QueryPlugin.java:280)
at com.xpn.xwiki.XWiki.search(XWiki.java:5374)
at com.xpn.xwiki.api.XWiki.search(XWiki.java:2610)