Never seen this problem with HFS, but I have with others. It could be that another program is interferring with it in some way.
Close all other programs, including taskbar-only apps that are not absolutely necessary. (Leave your Firewall and AV running if you have them. Those ARE necessary)
See if that helps at all. It could be a service, but that opens a big can o' worms you don't want to get into.
Only other suggestion is to re-download it (beta10) and start from scratch.
Next step would be an OS reload, but that depends on how important HFS is to ya.