Did you recently upgrade libc and is this a *bsd platform? A quick google search for the symbol __xuname indicated that this is a bsd problem with upgrading libc, and obviously the choices you have would be to concurrently upgrade libtcl and/or recompile libtcl against the new version of the libc and other libs you upgraded.. I don't know whether bsd platforms use ld-elf but in either case, you need to recompile libtcl against your new libs or upgrade to a binary package of libtcl thats already linked against the new libs..