LD_PRELOAD on x86_64 gives error from ld.so

I have implemented an interposer for open() and open64() system call.

This interposer is implemented in interposer.c and I have compiled it in a shared library (libinterposer.so) using the following commands:

gcc -g -fPIC -s -o interposer.o -c interposer.c
gcc -s -g -shared -nostartfiles -o libinterposer.so interposer.o -ldl

This interposer is working on i686 architecture. When I say working, it means, I can set the LD_PRELOAD environment variable to 'libinterposer.so' and intercept all 'open' system calls.

However when I repeat the exact same steps on a x86_64, I get errors from ld.so like so:

manmukhe@sjc-lds-133:[lbt]echo $LD_PRELOAD
libinterposer.x86_64.so

manmukhe@sjc-lds-133:[lbt]touch x.c
ERROR: ld.so: object 'libinterposer.x86_64.so' from LD_PRELOAD cannot be preloaded: ignored.

The file types for libinterposer.so and touch are as follows:

manmukhe@sjc-lds-133:[lbt]file libinterposer.x86_64.so
libinterposer.x86_64.so: ELF 64-bit LSB shared object, AMD x86-64, version 1 (SYSV), stripped

manmukhe@sjc-lds-133:[lbt]file /bin/touch
/bin/touch: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.4.0, dynamically linked (uses shared libs), stripped

Here are my questions:

  1. What am I doing wrong? Why am I getting the ld.so error?
  2. Is there any way to suppress the ld.so errors?