Error using Ferret - ferret/index.rb:271:in `delete'

We are using Ferret on our site answeru.com. Today all of a sudden we
started getting Ferret errors while users were trying to register or log
into the system. I am not a Ferret techie - I apologize if a similar
problem
has already been asked or if it is not really a Ferret issue.

Any ideas:

IO Error occured at <except.c>:79 in xraise
Error occured in fs_store.c:324 - fs_open_input
couldn’t create InStream
…/config/…/index/production/user/_dk8.fdt:

/home/packages/lib/ruby/gems/1.8/gems/ferret-0.10.13/lib/ferret/index.rb:271:in
`delete’


Anil

http://answeru.com