SharePoint unable to crawl AX data

Hi

I've setup search with SharePoint 2010 and for the Microsoft Dynamics AX content source it fails on all items with the error "Error while crawling LOB contents. ( The directory name is invalid. )".

I've looked online and no-one seems to have had this error, has anyone got any things I can check out for this?  It's running via the BDC service and the permissions are all set fine as far as I'm aware.

Thanks