R help - Nov 2007 - installing packages on OS X -- lgfortran problem

I am trying to install two packages that are not available at CRAN  
(rmutil, dna). When trying the R CMD INSTALL with either file, I get  
an error message that ends with

/usr/libexec/gcc/i686-apple-darwin8/4.0.1/libtool: can't locate file  
for: -lgfortran
/usr/libexec/gcc/i686-apple-darwin8/4.0.1/libtool: file: -lgfortran  
is not an object file (not allowed in a library)

Can anyone please help?
I have R 2.6 on a Macbook running 10.4.10. I have installed XCode 2.5.

A complete error message is given below.

Thank you!

Stefanie



* Installing to library '/Library/Frameworks/R.framework/Resources/ 
library'
* Installing *source* package 'rmutil' ...
** libs
** arch - i386
gcc-4.0 -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk - 
std=gnu99 -no-cpp-precomp -I/Library/Frameworks/R.framework/Resources/ 
include -I/Library/Frameworks/R.framework/Resources/include/i386  - 
msse3    -fPIC  -g -O2 -march=nocona -c cutil.c -o cutil.o
gcc-4.0 -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk - 
std=gnu99 -no-cpp-precomp -I/Library/Frameworks/R.framework/Resources/ 
include -I/Library/Frameworks/R.framework/Resources/include/i386  - 
msse3    -fPIC  -g -O2 -march=nocona -c dist.c -o dist.o
gfortran-4.0 -arch i386  -isysroot /Developer/SDKs/MacOSX10.4u.sdk   - 
fPIC  -g -O2 -march=nocona -c gettvc.f -o gettvc.o
gcc-4.0 -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk - 
std=gnu99 -no-cpp-precomp -I/Library/Frameworks/R.framework/Resources/ 
include -I/Library/Frameworks/R.framework/Resources/include/i386  - 
msse3    -fPIC  -g -O2 -march=nocona -c romberg.c -o romberg.o
gcc-4.0 -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk - 
std=gnu99 -no-cpp-precomp -I/Library/Frameworks/R.framework/Resources/ 
include -I/Library/Frameworks/R.framework/Resources/include/i386  - 
msse3    -fPIC  -g -O2 -march=nocona -c toms614.c -o toms614.o
gcc-4.0 -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk - 
std=gnu99 -dynamiclib -Wl,-headerpad_max_install_names -Wl,- 
macosx_version_min -Wl,10.3 -undefined dynamic_lookup -single_module - 
multiply_defined suppress -o rmutil.so cutil.o dist.o gettvc.o  
romberg.o toms614.o -L/usr/local/lib/gcc/i686-apple-darwin8/4.2.1 - 
lgfortran -lgcc_s.10.4
/usr/libexec/gcc/i686-apple-darwin8/4.0.1/libtool: can't locate file  
for: -lgfortran
/usr/libexec/gcc/i686-apple-darwin8/4.0.1/libtool: file: -lgfortran  
is not an object file (not allowed in a library)
make: *** [rmutil.so] Error 1
ERROR: compilation failed for package 'rmutil'
** Removing '/Library/Frameworks/R.framework/Versions/2.6/Resources/ 
library/rmutil'