[darcs-users] Darcs fails waiting for lock file

[Jon Hart]

It looks like there is some garbage left over from a previous darcs  
invocation, the following files arent present in my other repositories:

lock
tentative_hashed_inventory
tentative_pristine

The repository only has a single user, so no other instances should  
have those files. Is it safe for me to delete them?
What is a likely cause of their presence? Would they be left behind if  
darcs was terminated?

Jon Hart.