This is one of potential issue after applying APAR 50891. Solr pre-processing fails on following file
wc-dataimport-preprocess-catgroup-global-sequence.xml with exception null pointer exception.
Here is solution.
This feature don't like null values in sequence column. just try to run queries inside wc-dataimport-preprocess-catgroup-global-sequence.xml and if you observe any null value in sequence column. Update it with 0 value.
