I have seen many posts on this problem. I have finally found a solution, which is outlined below:
I have Fedora 12 x86_64 version on Core I7 CPU.
Wrote a simple "hello world" program and compiled it using "gcc -m32 ...". Could not compile. Went through many trials and errors and discovered that the following cured the problems:
yum install glibc.i686 # For the basic libs.
yum install glibc-devel.i686 # For stubs.
yum install compat-libstdc++-33-3.2.3-68.i686 # For compatibility of 32 bits on 64 bit CPU.
yum install compat-libstdc++-296-2.96-143.i686
The programs compiles and runs OK. Hope the above helps.