Installing Packages on an Athlon 64 Linux System

I installed FC 2 X86-64 on an Athlon 64 system. I then installed R 
2.0.0. It runs fine except when I try to install or update packages 
using either "install.packages" or "update.packages". I get the 
following types of errors:

gcc -I/usr/lib/R/include  -I/usr/local/include -D__NO_MATH_INLINES 
-mieee-fp  -fPIC  -O2 -g -pipe -march=i386 -mcpu=i686 -c block.c -o block.o
cc1: error: CPU you selected does not support x86-64 instruction set
cc1: error: CPU you selected does not support x86-64 instruction set
make: *** [block.o] Error 1
ERROR: compilation failed for package 'gstat'
** Removing '/usr/lib/R/library/gstat'
** Restoring previous '/usr/lib/R/library/gstat'
 
How can I fix this?

Rick B.