Lenskit error: recommender has no item recommender

Question

I am trying to use Lenskit with the ml-100k/u.data dataset and I want to generate Top-N recommendations for the users. From the lenskit folder, I am executing:

/bin/bash  build/install/lenskit/bin/lenskit recommend 42 -n 5 --csv-file=data/ml-100k/u.data

And I get the following output when executing the code:

INFO  14:58:03.934 [main] org.lenskit.cli.Main Starting LensKit 3.0-SNAPSHOT on Java 1.8.0_40 from Oracle Corporation
INFO  14:58:03.982 [main] org.lenskit.cli.Main Have 4 processors and heap limit of 2626 MiB
INFO  14:58:03.983 [main] o.l.c.u.RecommenderLoader creating fresh recommender
INFO  14:58:06.473 [main] o.l.c.u.RecommenderLoader built recommender in 2.485 s
ERROR 14:58:09.253 [main] o.l.c.commands.Recommend recommender has no item recommender
Exception in thread "main" java.lang.UnsupportedOperationException: no item recommender
        at org.lenskit.cli.commands.Recommend.execute(Recommend.java:90)
        at org.lenskit.cli.Main.main(Main.java:73)

I understand I am most likely missing the "Scoring Items", but I am not able to figure out how to compute these. I am completely new with the programme, so any help or advise is very much appreciated.

Thanks in advance!