I'm attempting to install the gsl package using the following command: install.packages("c:/users/mike/documents/R/win-library/gsl_1.9-9.tar.gz",repos=NULL,type="source") My attempt is failing. Please help. The message supplied is: Installing package(s) into ‘C:/Users/Mike/Documents/R/win-library/2.15’ (as ‘lib’ is unspecified) * installing *source* package 'gsl' ... ** package 'gsl' successfully unpacked and MD5 sums checked ********************************************** WARNING: this package has a configure script It probably needs manual configuration ********************************************** ** libs gcc -m64 -I"C:/PROGRA~1/R/R-215~1.0/include" -DNDEBUG -I/include -I"d:/RCompile/CRANpkg/extralibs64/local/include" -O2 -Wall -std=gnu99 -mtune=core2 -c airy.c -o airy.o airy.c:1: sorry, unimplemented: 64-bit mode not compiled in airy.c:1: error: bad value (core2) for -mtune= switch C:/PROGRA~1/R/R-215~1.0/etc/x64/Makeconf:172: recipe for target `airy.o' failed make: *** [airy.o] Error 1 ERROR: compilation failed for package 'gsl' * removing 'C:/Users/Mike/Documents/R/win-library/2.15/gsl' Warning messages: 1: running command 'C:/PROGRA~1/R/R-215~1.0/bin/x64/R CMD INSTALL -l "C:/Users/Mike/Documents/R/win-library/2.15" "c:/users/mike/documents/R/win-library/gsl_1.9-9.tar.gz"' had status 1 2: In install.packages("c:/users/mike/documents/R/win-library/gsl_1.9-9.tar.gz", : installation of package ‘c:/users/mike/documents/R/win-library/gsl_1.9-9.tar.gz’ had non-zero exit status [[alternative HTML version deleted]]