While installing ffi-0.6.2 ,I am facing on problem.

My PC runs on Windows XP.

I have already have gem version 1.3.6 and ruby 1.8.7 <2010 01-10
patchlevel 249> [i386-mingw32]

but it fails and on command prompt throws this error:


Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\sabhu>d:

D:\>gem install ffi --version 0.6.2
Building native extensions.  This could take a while...
ERROR:  Error installing ffi:
        ERROR: Failed to build gem native extension.

C:/Ruby/bin/ruby.exe extconf.rb
checking for rb_thread_blocking_region()... no
creating extconf.h
creating Makefile

make
Configuring libffi
rm: cannot lstat `conftest.er1': Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3413:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3560:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3560:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3560:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3642:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3642:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3642:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3642:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3642:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3642:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 3642:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
rm: cannot lstat `conftest.er1': Permission denied
rm: cannot lstat `conftest.er1': Permission denied
rm: cannot lstat `conftest.er1': Permission denied
rm: cannot lstat `conftest.er1': Permission denied
rm: cannot lstat `conftest.er1': Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 6813:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 6813:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 6813:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 6813:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 6813:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 6813:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/libffi/configure:
line 6920:
conftest.er1: Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
grep: conftest.er1: Permission denied
rm: cannot lstat `conftest.er1': Permission denied
configure: error: in `/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/
ffi_c/libffi'
:
configure: error: C preprocessor "/lib/cpp" fails sanity check
See `config.log' for more details.
rm: cannot lstat `conftest.er1': Permission denied
make: *** [/c/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/
libffi/.libs/libff
i_convenience.a] Error 1


Gem files will remain installed in C:/Ruby/lib/ruby/gems/1.8/gems/
ffi-0.6.2 for
inspection.
Results logged to C:/Ruby/lib/ruby/gems/1.8/gems/ffi-0.6.2/ext/ffi_c/
gem_make.ou
t

D:\>