Hi. I have a suspection you may use gcc compiler of version 4 or higher. In such a case you will need libgfortran instead of libg2c. Please verify the version of the compiler you use ("gcc --version"). See also below. On 10/21/07, Johann Rost wrote: > What are these libraries with extension .so and .so.0 > .so.0.0 for? Are they shared libraries? And why exist These are shared libraries, like "dll" files under windows. The 2 numbers after the ".so" denote the version and the subversion. If exists, ".so.X.Y" is the library itself and ".so.X" and ".so" are solf links to it. (You can verify this by doing " ls -l /usr/lib/libg2c* " )