diff --git a/IPython/Extensions/ipipe.py b/IPython/Extensions/ipipe.py
index e76e0c3..7f9029a 100644
--- a/IPython/Extensions/ipipe.py
+++ b/IPython/Extensions/ipipe.py
@@ -114,6 +114,11 @@ except NameError:
             items.reverse()
         return items
 
+try: # Python 2.4 compatibility
+    GeneratorExit
+except NameError:
+    GeneratorExit = SystemExit
+
 try:
     import pwd
 except ImportError:
@@ -666,7 +671,7 @@ def xrepr(item, mode="default"):
         try:
             for x in func(mode):
                 yield x
-        except (KeyboardInterrupt, SystemExit):
+        except (KeyboardInterrupt, SystemExit, GeneratorExit):
             raise
         except Exception:
             yield (astyle.style_default, repr(item))
@@ -840,20 +845,20 @@ def upgradexattr(attr):
     """
     Convert an attribute descriptor string to a real descriptor object.
 
-    If attr already is a descriptor object return if unmodified. A
+    If attr already is a descriptor object return it unmodified. A
     ``SelfDescriptor`` will be returned if ``attr`` is ``None``. ``"foo"``
     returns an ``AttributeDescriptor`` for the attribute named ``"foo"``.
     ``"foo()"`` returns a ``MethodDescriptor`` for the method named ``"foo"``.
     ``"-foo"`` will return an ``IterAttributeDescriptor`` for the attribute
     named ``"foo"`` and ``"-foo()"`` will return an ``IterMethodDescriptor``
-    for the method named ``"foo"``. Furthermore integer will return the appropriate
+    for the method named ``"foo"``. Furthermore integers will return the appropriate
     ``IndexDescriptor`` and callables will return a ``FunctionDescriptor``.
     """
     if attr is None:
         return selfdescriptor
     elif isinstance(attr, Descriptor):
         return attr
-    elif isinstance(attr, str):
+    elif isinstance(attr, basestring):
         if attr.endswith("()"):
             if attr.startswith("-"):
                 return IterMethodDescriptor(attr[1:-2])
diff --git a/IPython/Magic.py b/IPython/Magic.py
index 32bdb6d..a6194ca 100644
--- a/IPython/Magic.py
+++ b/IPython/Magic.py
@@ -1675,7 +1675,7 @@ Currently the magic system has the following functions:\n"""
                                    exit_ignore=exit_ignore)
                             t1 = clock2()
                             t_usr = t1[0]-t0[0]
-                            t_sys = t1[1]-t1[1]
+                            t_sys = t1[1]-t0[1]
                             print "\nIPython CPU timings (estimated):"
                             print "  User  : %10s s." % t_usr
                             print "  System: %10s s." % t_sys
@@ -1687,7 +1687,7 @@ Currently the magic system has the following functions:\n"""
                                        exit_ignore=exit_ignore)
                             t1 = clock2()
                             t_usr = t1[0]-t0[0]
-                            t_sys = t1[1]-t1[1]
+                            t_sys = t1[1]-t0[1]
                             print "\nIPython CPU timings (estimated):"
                             print "Total runs performed:",nruns
                             print "  Times : %10s    %10s" % ('Total','Per run')
diff --git a/IPython/Shell.py b/IPython/Shell.py
index 5454f7b..2dd9dac 100644
--- a/IPython/Shell.py
+++ b/IPython/Shell.py
@@ -292,17 +292,19 @@ if HAS_CTYPES:
         """raises the exception, performs cleanup if needed"""
         if not inspect.isclass(exctype):
             raise TypeError("Only types can be raised (not instances)")
-        res = ctypes.pythonapi.PyThreadState_SetAsyncExc(tid,
+        # Explicit cast to c_long is necessary for 64-bit support:
+        # See https://bugs.launchpad.net/ipython/+bug/237073
+        res = ctypes.pythonapi.PyThreadState_SetAsyncExc(ctypes.c_long(tid),
                                                          ctypes.py_object(exctype))
         if res == 0:
             raise ValueError("invalid thread id")
         elif res != 1:
-            # """if it returns a number greater than one, you're in trouble, 
-            # and you should call it again with exc=NULL to revert the effect"""
+            # If it returns a number greater than one, you're in trouble, 
+            # and you should call it again with exc=NULL to revert the effect
             ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, 0)
             raise SystemError("PyThreadState_SetAsyncExc failed")
 
-    def sigint_handler (signum,stack_frame):
+    def sigint_handler(signum,stack_frame):
         """Sigint handler for threaded apps.
 
         This is a horrible hack to pass information about SIGINT _without_
@@ -321,7 +323,7 @@ if HAS_CTYPES:
             Term.cout.flush()
 
 else:
-    def sigint_handler (signum,stack_frame):
+    def sigint_handler(signum,stack_frame):
         """Sigint handler for threaded apps.
 
         This is a horrible hack to pass information about SIGINT _without_
diff --git a/IPython/background_jobs.py b/IPython/background_jobs.py
index e418aaa..c5998c3 100644
--- a/IPython/background_jobs.py
+++ b/IPython/background_jobs.py
@@ -248,7 +248,7 @@ class BackgroundJobManager:
         self._update_status()
         new_comp = self._group_report(self._comp_report,'Completed')
         new_dead = self._group_report(self._dead_report,
-                                      'Dead, call job.traceback() for details')
+                                      'Dead, call jobs.traceback() for details')
         self._comp_report[:] = []
         self._dead_report[:] = []
         return new_comp or new_dead
@@ -340,7 +340,7 @@ class BackgroundJobBase(threading.Thread):
     stat_created   = 'Created'; stat_created_c = 0
     stat_running   = 'Running'; stat_running_c = 1
     stat_completed = 'Completed'; stat_completed_c = 2
-    stat_dead      = 'Dead (Exception), call job.traceback() for details'
+    stat_dead      = 'Dead (Exception), call jobs.traceback() for details'
     stat_dead_c = -1
 
     def __init__(self):
@@ -391,7 +391,7 @@ class BackgroundJobBase(threading.Thread):
             self.status    = BackgroundJobBase.stat_dead
             self.stat_code = BackgroundJobBase.stat_dead_c
             self.finished  = None
-            self.result    = ('<BackgroundJob died, call job.traceback() for details>')
+            self.result    = ('<BackgroundJob died, call jobs.traceback() for details>')
             self._tb       = self._make_tb()
         else:
             self.status    = BackgroundJobBase.stat_completed