Cannot automount USB flash drives on FC6

[Duncan Brown]

Hey all

Since upgrading to FC6 usb drives no longer automount. When inserted 
they are recognised and all the normal log messages appear, but then i 
get a warning:

Cannot mount Volume

Cannot obtain lock on /media/.hal-mtab

I can mount the drives manually no problem though. I've seen quite a few 
posts about USB drives but none mentioning this specific error. Googling 
the error gives very little too

Any ideas?

thanks

Dunc