I'm trying to dynamically create a lot of documents all at once the API seems to been handeling this very well but the ExamineIndex is failing.

Part way through the creation I recieve this error:

System.IO.IOException: The process cannot access the file 'UMBRACO_PATH\App_Data\TEMP\ExamineIndexes\Internal\COMPUTER.lck' because it is being used by another process.
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options)
   at System.IO.StreamWriter.CreateFile(String path, Boolean append)
   at System.IO.StreamWriter..ctor(String path, Boolean append, Encoding encoding, Int32 bufferSize)
   at System.IO.StreamWriter..ctor(String path, Boolean append)
   at System.IO.FileInfo.CreateText()
   at Examine.LuceneEngine.SerializableDictionaryExtensions.SaveToDisk[TKey,TValue](SerializableDictionary`2 sd, FileInfo fi)
   at Examine.LuceneEngine.IndexerExecutive.TimestampLck()
   at Examine.LuceneEngine.IndexerExecutive.get_IsExecutiveMachine()
   at Examine.LuceneEngine.Providers.LuceneIndexer.SafelyProcessQueueItems()
   at Examine.LuceneEngine.Providers.LuceneIndexer.AddNodesToIndex(IEnumerable`1 nodes, String type)
   at UmbracoExamine.UmbracoContentIndexer.AddSingleNodeToIndex(XElement node, String type)
   at Examine.LuceneEngine.Providers.LuceneIndexer.ReIndexNode(XElement node, String type)
   at UmbracoExamine.BaseUmbracoIndexer.ReIndexNode(XElement node, String type)
   at UmbracoExamine.UmbracoContentIndexer.ReIndexNode(XElement node, String type)
   at Examine.ExamineManager._ReIndexNode(XElement node, String type, IEnumerable`1 providers)
   at UmbracoExamine.UmbracoEventManager.IndexMedia(Media sender)
   at UmbracoExamine.UmbracoEventManager.Document_AfterSave(Document sender, SaveEventArgs e)
   at umbraco.cms.businesslogic.web.Document.SaveEventHandler.Invoke(Document sender, SaveEventArgs e)
   at umbraco.cms.businesslogic.web.Document.FireAfterSave(SaveEventArgs e)
   at umbraco.cms.businesslogic.web.Document.Save()
   at PROJECT.Core.Code.Migration.MigrateServices.SaveServicesToUmbraco(IList`1 services) in UMBRACO_PATH\Code\Migration\MigrateServices.cs:line 510
   at PROJECT.Core.usercontrols.MigrateServices.MigrateContent_Click(Object sender, EventArgs e) in UMBRACO_PATH\usercontrols\MigrateServices.ascx.cs:line 25

So far i've followed Shannon's instructions :

Delete your entire Examine folder with all indexes (if you get file 
lock errors, it means that something is still hanging on to the files, 
you'll have to bump your web.config file)
Reset file/folder permissions on App_Data to make sure that the IIS user can read/write/delete (full control)
Set your indexers to run in async mode.
Log into Umbraco and publish 1 node... this will re-index all of your content.
Wait about a minute for the async operations to work.

I've worked with Lucene before and had all kinds of problems with Locking indexes, in this case i'd even be happy to turn the index off for a period as an initial work around.

Cheers

Jon