Thanks, it's giving this, so it's appears to be 32 bit (I compiled with CFLAGS=-m32): /usr/local/lib/libocilib.dylib: Mach-O dynamically linked shared library i386 I think the library is ok, it's just not being found by Pharo when I launch it as an application from the Finder dialog. If I launch Pharo from a terminal window,like ./Pharo, it finds the library using DYLD_LIBRARY_PATH and DYLD_FALLBACK_LIBRARY_PATH, it doesn't even need a sym link in the Pharo Plugins directory and the library is found by Pharo and works. If I create a sym link in the Plugins directory or copy the dylib to the Plugins directory and launch Pharo via the Finder dialog window, it fails with "External module not found", so it appears to be how Pharo and/or OSX sets it library path when launched as an Application that is causing the issue. Thanks.