I reported a problem like this on the list a little while ago but this crash looks a little different so I thought I would post the stack trace I got from gdb. Please ignore this if it is already a known problem. #0 0x401bb811 in __kill () #1 0x401bb63f in raise (sig=6) at ../sysdeps/posix/raise.c:27 #2 0x401bc84f in abort () at ../sysdeps/generic/abort.c:83 #3 0x401b6416 in __assert_fail ( assertion=0x4019018f "!!!\"Attempt to explicitly free nonfixed object\"", file=0x4018fd38 "../../../kaffe/kaffevm/mem/gc-incremental.c", line=964, function=0x40190188 "gcFree") at assert.c:54 #4 0x4015c3ed in gcFree (gcif=0x40199e38, mem=0x89051e8) at ../../../kaffe/kaffevm/mem/gc-incremental.c:964 #5 0x4015c75b in jfree (mem=0x89051e8) at ../../../kaffe/kaffevm/gc.c:33 #6 0x4024e57e in freevec (v=0x89051c0) at ../../../../libraries/clib/native/UNIXProcess.c:36 #7 0x4024e886 in Java_kaffe_lang_UNIXProcess_forkAndExec (env=0x4019473c, proc=0x887bf88, args=0x85bd8b8, envs=0x0) at ../../../../libraries/clib/native/UNIXProcess.c:132 #8 0x85b37ad in ?? () #9 0x8712d54 in ?? () #10 0x4016fd44 in callMethodV (meth=0x8714ad8, func=0x868d546, obj=0x887bf88, args=0xbfffdb28, ret=0xbfffda00) at ../../../config/i386/common.h:38 #11 0x4016f576 in execute_java_constructor_v ( cname=0x40253c5f "kaffe.lang.UNIXProcess", cc=0x0, signature=0x40253c35 "([Ljava/lang/String;[Ljava/lang/String;)V", argptr=0xbfffdb20) at ../../../kaffe/kaffevm/support.c:201 #12 0x4016f5a6 in execute_java_constructor ( cname=0x40253c5f "kaffe.lang.UNIXProcess", cc=0x0, signature=0x40253c35 "([Ljava/lang/String;[Ljava/lang/String;)V") at ../../../kaffe/kaffevm/support.c:213 #13 0x4024d7b3 in java_lang_Runtime_execInternal (this=0x818fe08, argv=0x85bd8b8, arge=0x0) at ../../../../libraries/clib/native/Runtime.c:110 #14 0x822f5be in ?? () ... #61 0x4016fd44 in callMethodV (meth=0x822f5e0, func=0x821c878, obj=0x0, args=0xbffff0ac, ret=0xbfffef18) at ../../../config/i386/common.h:38 #62 0x401663ef in Kaffe_CallStaticVoidMethodV (env=0x4019473c, cls=0x81940c0, meth=0x822f5e0, args=0xbffff0a8) at ../../../kaffe/kaffevm/jni.c:2345 #63 0x40166468 in Kaffe_CallStaticVoidMethod (env=0x4019473c, cls=0x81940c0, meth=0x822f5e0) at ../../../kaffe/kaffevm/jni.c:2358 #64 0x8048be4 in main2 (env=0x4019473c, argv=0xbffff514, farg=4, argc=0) at ../../../kaffe/kaffe/main.c:195 #65 0x8048ac2 in main (argc=4, argv=0xbffff514) at ../../../kaffe/kaffe/main.c:115 I hope that helps Mo DeJong