diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index 9a09c7d..7966e0a 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -540,7 +540,9 @@
 	int size;
 	arrayobject *np;
 	if (!is_arrayobject(bb)) {
-		PyErr_BadArgument();
+		PyErr_Format(PyExc_TypeError,
+		     "can only append array (not \"%.200s\") to array",
+			     bb->ob_type->tp_name);
 		return NULL;
 	}
 #define b ((arrayobject *)bb)
@@ -613,7 +615,9 @@
 		}
 	}
 	else {
-		PyErr_BadArgument();
+		PyErr_Format(PyExc_TypeError,
+	     "can only assign array (not \"%.200s\") to array slice",
+			     v->ob_type->tp_name);
 		return -1;
 	}
 	if (ilow < 0)
@@ -821,7 +825,8 @@
 	char tmp[sizeof(double)]; /* Assume that's the max item size */
 
 	if (args != NULL) {
-		PyErr_BadArgument();
+		PyErr_SetString(PyExc_TypeError,
+		     "<array>.reverse requires exactly 0 arguments");
 		return NULL;
 	}
 
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 1ca3826..20efb0e 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -1562,8 +1562,7 @@
 		getitem = PyTuple_GetItem;
 	}
 	else {
- badarg:
-		PyErr_BadArgument();
+		PyErr_SetString(PyExc_TypeError, "argv must be tuple or list");
 		return NULL;
 	}
 
@@ -1573,7 +1572,9 @@
 	for (i = 0; i < argc; i++) {
 		if (!PyArg_Parse((*getitem)(argv, i), "s", &argvlist[i])) {
 			PyMem_DEL(argvlist);
-			goto badarg;
+			PyErr_SetString(PyExc_TypeError, 
+					"all arguments must be strings");
+			return NULL;
 		}
 	}
 	argvlist[argc] = NULL;
diff --git a/Modules/structmodule.c b/Modules/structmodule.c
index 0a706a9..d872e31 100644
--- a/Modules/structmodule.c
+++ b/Modules/structmodule.c
@@ -1128,7 +1128,8 @@
 	if (args == NULL || !PyTuple_Check(args) ||
 	    (n = PyTuple_Size(args)) < 1)
         {
-		PyErr_BadArgument();
+		PyErr_SetString(PyExc_TypeError, 
+			"struct.pack requires at least one argument");
 		return NULL;
 	}
 	format = PyTuple_GetItem(args, 0);