I'm getting this error on posting to a topic:

Could not find file '\\n5200-2\iis7_www\a\r\mysite\www\App_Data\TEMP\ExamineIndexes\nForumEntryIndexSet\Index\segments_a'.

[FileNotFoundException: Could not find file '\\n5200-2\iis7_www\a\r\mysite\www\App_Data\TEMP\ExamineIndexes\nForumEntryIndexSet\Index\segments_a'.]
   Lucene.Net.Index.FindSegmentsFile.Run(IndexCommit commit) +2040
   Lucene.Net.Index.SegmentInfos.Read(Directory directory) +68
   Lucene.Net.Index.SegmentInfos.ReadCurrentVersion(Directory directory) +35
   Lucene.Net.Index.DirectoryReader.IsCurrent() +43
   Examine.LuceneEngine.LuceneExtensions.GetReaderStatus(IndexReader reader) +35
   Examine.LuceneEngine.Providers.LuceneSearcher.ValidateSearcher(Boolean forceReopen) +260
   Examine.LuceneEngine.Providers.LuceneSearcher.GetSearchFields() +15
   UmbracoExamine.UmbracoExamineSearcher.GetSearchFields() +9
   Examine.LuceneEngine.Providers.BaseLuceneSearcher.CreateSearchCriteria(String type, BooleanOperation defaultOperation) +29
   UmbracoExamine.UmbracoExamineSearcher.CreateSearchCriteria(String type, BooleanOperation defaultOperation) +9
   Examine.LuceneEngine.Providers.BaseLuceneSearcher.CreateSearchCriteria() +18
   nForum.BusinessLogic.Data.ForumFactory.ReturnAllPostsInTopic(Int32 topicNodeId, Boolean useNodeFactory) in nForum.BusinessLogic\Data\ForumFactory.cs:330

After digging around I found that it could be caused by mulitple processes accessing the lucene index at the same time and corrupting it.

I've cleared the indexes in temp, and re-indexed but still get the same issue.

Anyone come across this? any ideas?

How can I find out what else is accessing Lucene?

Thanks
Pete