I am trying to install the R package "Rmpi" which needs libmpi. I've installed openmpi and lam in Centos 5.2: [root at rab45-1 /]# rpm -qv openmpi openmpi-1.2.5-5.el5 openmpi-1.2.5-5.el5 [root at rab45-1 /]# rpm -qv lam lam-7.1.2-14.el5 lam-7.1.2-14.el5 I'm using this to install Rmpi: R CMD INSTALL /home/rick/Rmpi_0.5-7.tar.gz --with-mpi=/usr/lib64/lam/include But I get the following error message: /usr/bin/ld: skipping incompatible /usr/lib/lam/lib/libmpi.so when searching for -lmpi I'm not sure what else to install/uninstall to fix this. Rick B.