get_filename() fails in exit_process() event handler

[malwaremuser]

C:\Python27\lib\site-packages\winappdbg\event.py:1855: EventCallbackWarning: Event handler pre-callback <main.MyEventHandler object at 0x00B18210> raised an exception: Traceback (most recent call last):
File "C:\Python27\lib\site-packages\winappdbg\event.py", line 1850, in dispatch
returnValue = self.eventHandler(event)
File "C:\Python27\lib\site-packages\winappdbg\event.py", line 1467, in __call
return method(event)
File "E:\unpack.py", line 895, in exit_process
log("[*] <%d:%d> Exit process event for %s: %d" % (pid,tid,event.get_filename(),event.get_exit_code()))
File "C:\Python27\lib\site-packages\winappdbg\event.py", line 926, in get_filename
return self.get_module().get_filename()
File "C:\Python27\lib\site-packages\winappdbg\event.py", line 947, in get_module
return self.get_process().get_main_module()
File "C:\Python27\lib\site-packages\winappdbg\process.py", line 931, in get_main_module
return self.get_module(self.get_image_base())
File "C:\Python27\lib\site-packages\winappdbg\module.py", line 907, in get_module
raise KeyError(msg)
KeyError: 'Unknown DLL base address 00400000'