Preconfiguring packages ...
(Reading database ... 22879 files and directories currently installed.)
Preparing to replace libc6 2.3.6.ds1-8 (using .../libc6_2.5-9+b1_i386.deb) ...
WARNING: POSIX threads library NPTL requires kernel version
2.6.1 or later. If you use a kernel 2.4, please upgrade it
before installing glibc.
dpkg: error processing /var/cache/apt/archives/libc6_2.5-9+b1_i386.deb (--unpack):
 subprocess pre-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/libc6_2.5-9+b1_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)