An error occurred while attaching module (Dynamicweb.Frontend.Content)

System.NullReferenceException: Object reference not set to an instance of an object.
   at Lucene.Net.Store.SimpleFSDirectory.SimpleFSIndexInput.ReadInternal(Byte[] b, Int32 offset, Int32 len) in d:\Lucene.Net\FullRepo\trunk\src\core\Store\SimpleFSDirectory.cs:line 154
   at Lucene.Net.Store.BufferedIndexInput.Refill() in d:\Lucene.Net\FullRepo\trunk\src\core\Store\BufferedIndexInput.cs:line 186
   at Lucene.Net.Store.BufferedIndexInput.ReadByte() in d:\Lucene.Net\FullRepo\trunk\src\core\Store\BufferedIndexInput.cs:line 41
   at Lucene.Net.Store.IndexInput.ReadVInt() in d:\Lucene.Net\FullRepo\trunk\src\core\Store\IndexInput.cs:line 88
   at Lucene.Net.Index.TermBuffer.Read(IndexInput input, FieldInfos fieldInfos) in d:\Lucene.Net\FullRepo\trunk\src\core\Index\TermBuffer.cs:line 74
   at Lucene.Net.Index.SegmentTermEnum.Next() in d:\Lucene.Net\FullRepo\trunk\src\core\Index\SegmentTermEnum.cs:line 145
   at Lucene.Net.Index.SegmentMergeInfo.Next() in d:\Lucene.Net\FullRepo\trunk\src\core\Index\SegmentMergeInfo.cs:line 82
   at Lucene.Net.Index.DirectoryReader.MultiTermEnum.Next() in d:\Lucene.Net\FullRepo\trunk\src\core\Index\DirectoryReader.cs:line 1253
   at Lucene.Net.Search.FilteredTermEnum.Next() in d:\Lucene.Net\FullRepo\trunk\src\core\Search\FilteredTermEnum.cs:line 88
   at Lucene.Net.Search.WildcardQuery.GetEnum(IndexReader reader) in d:\Lucene.Net\FullRepo\trunk\src\core\Search\WildcardQuery.cs:line 61
   at Lucene.Net.Search.MultiTermQuery.ConstantScoreAutoRewrite.Rewrite(IndexReader reader, MultiTermQuery query) in d:\Lucene.Net\FullRepo\trunk\src\core\Search\MultiTermQuery.cs:line 271
   at Lucene.Net.Search.WildcardQuery.Rewrite(IndexReader reader) in d:\Lucene.Net\FullRepo\trunk\src\core\Search\WildcardQuery.cs:line 85
   at Lucene.Net.Search.BooleanQuery.Rewrite(IndexReader reader) in d:\Lucene.Net\FullRepo\trunk\src\core\Search\BooleanQuery.cs:line 463
   at Lucene.Net.Search.BooleanQuery.Rewrite(IndexReader reader) in d:\Lucene.Net\FullRepo\trunk\src\core\Search\BooleanQuery.cs:line 482
   at Lucene.Net.Search.BooleanQuery.Rewrite(IndexReader reader) in d:\Lucene.Net\FullRepo\trunk\src\core\Search\BooleanQuery.cs:line 463
   at Lucene.Net.Search.IndexSearcher.Rewrite(Query original) in d:\Lucene.Net\FullRepo\trunk\src\core\Search\IndexSearcher.cs:line 302
   at Lucene.Net.Search.Query.Weight(Searcher searcher) in d:\Lucene.Net\FullRepo\trunk\src\core\Search\Query.cs:line 96
   at Lucene.Net.Search.Searcher.Search(Query query, Filter filter, Int32 n, Sort sort) in d:\Lucene.Net\FullRepo\trunk\src\core\Search\Searcher.cs:line 57
   at Dynamicweb.Indexing.Lucene.LuceneIndexProvider.FillFacetFieldTerms(Facet facet, FieldDefinitionBase field, IndexReader reader, Query searchQuery, QuerySettings settings, FacetGroupResult facetsResult, IList`1 exceptions)
   at Dynamicweb.Indexing.Lucene.LuceneIndexProvider.FillFacetResultUsingSpecializedQuery(Facet facet, FieldDefinitionBase field, IndexReader reader, Query searchQuery, QuerySettings settings, FacetGroupResult facetsResult, IList`1 exceptions)
   at Dynamicweb.Indexing.Lucene.LuceneIndexProvider.DoFacetSearch(IFacetGroup facets, FieldDefinitionBase[] fields, IndexReader reader, IQuery query, QuerySettings settings, Query originalQuery, IList`1 exceptions)
   at Dynamicweb.Indexing.Lucene.LuceneIndexProvider.SearchInternal(IQuery query, QuerySettings settings)
   at Dynamicweb.Indexing.Querying.QueryService.Query(IQuery query, QuerySettings settings)
   at Dynamicweb.QueryPublisher.Frontend.GetContent()
   at Dynamicweb.Frontend.Content.GetModuleOutput(Paragraph paragraph, PageView pageview)