If you are creating a Custom Property Extractor for FAST for SharePoint 2010 be careful because careful to set up your Extraction Dictionary correctly. I recently had a colleague create a new extraction dictionary like in here - http://msdn.microsoft.com/en-us/library/ff795797.aspx
Unfortunately I do not have the logs but my colleague was telling me that FAST was just hanging when trying to execute the FAST crawl. I looked at the modifications he made and took a guess that the ampersands he had throughout the custom property extraction dictionary XML definition could be the issue. I recommended he remove the ampersands and replace with &. Well that took care of the issue.