Rename error using rebuild_index in console after searching

Hi,
I use ruby console to experiment acts_as_ferret, but I ran into file
rename error when I try to rebuild index after doing a search.

is this normal? I am using Ferret 0.10.9 in windows XP.

Loading development environment.

Address.rebuild_index
=> {}

Address.find_by_contents(‘US’)
=> #<ActsAsFerret::SearchResults:0x4f2ffcc @total_hits=2,
@results=[#<Address:0x
4f30198 @ferret_score=0.106434106826782, @ferret_rank=1,
@attributes={“city”=>""
, “updated_at”=>“2007-04-16 01:32:40”, “zipcode”=>“11111”,
“addressable_type”=>"
User", “country”=>“US”, “addressable_id”=>“1”, “id”=>“1”, “line_1”=>"",
“line_2”
=>"", “created_at”=>“2007-03-19 22:06:04”, “state”=>“Alaska”}>,
#<Address:0x4f30
06c @ferret_score=0.106434106826782, @ferret_rank=2,
@attributes={“city”=>“san f
ran”, “updated_at”=>“2007-04-01 16:32:43”, “zipcode”=>“94579”,
“addressable_type
“=>“User”, “country”=>“US”, “addressable_id”=>“4”, “id”=>“4”,
“line_1”=>“12”, “l
ine_2”=>””, “created_at”=>“2007-03-25 14:44:35”,
“state”=>“California”}>]>

Address.rebuild_index
IOError: IO Error occured:
couldn’t rename file
“./script/…/config/…/config/…/index/development/address
_3.tmp” to
“./script/…/config/…/config/…/index/development/address_3.cfs”: <
File exists>

    from

C:/InstantRails-1.6-win/ruby/lib/ruby/gems/1.8/gems/ferret-0.10.9-m
swin32/lib/ferret/index.rb:529:in optimize' from C:/InstantRails-1.6-win/ruby/lib/ruby/gems/1.8/gems/ferret-0.10.9-m swin32/lib/ferret/index.rb:529:inoptimize’
from C:/InstantRails-1.6-win/ruby/lib/ruby/1.8/monitor.rb:238:in
synchr onize' from C:/InstantRails-1.6-win/ruby/lib/ruby/gems/1.8/gems/ferret-0.10.9-m swin32/lib/ferret/index.rb:527:inoptimize’
from
./script/…/config/…/config/…/vendor/plugins/acts_as_ferret/lib/l
ocal_index.rb:51:in rebuild_index' from ./script/../config/../config/../vendor/plugins/acts_as_ferret/lib/c lass_methods.rb:15:inrebuild_index’
from (irb):3

Thanks.
yaxm