Access is Denied loading a dll with ctypes on Vista

Question

I'm having issues with using ctypes. I'm trying to get the following project running on Vista.

http://sourceforge.net/projects/fractalfrost/

I've used the project before on Vista and had no problems. I don't see any think changed in svn that cause this I'm thinking it's something local to this machine. In fact I'm not able to load dll's with ctypes at all.

Bobby@Teresa-PC ~/fr0st-exe/fr0st/pyflam3/win32_dlls
$ ls
Flam4CUDA_LIB.dll cudart.dll glew32.dll libflam3.dll pthreadVC2.dll

Bobby@Teresa-PC ~/fr0st-exe/fr0st/pyflam3/win32_dlls
$ python
Python 2.6.3 (r263rc1:75186, Oct 2 2009, 20:40:30) [MSC v.1500 32 bit (Intel)]
on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from ctypes import *
>>> flam3_dll = CDLL('libflam3.dll')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "c:\Python26\lib\ctypes\__init__.py", line 353, in __init__
    self._handle = _dlopen(self._name, mode)
WindowsError: [Error 5] Access is denied
>>> flam3_dll = CDLL('.\\libflam3.dll')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "c:\Python26\lib\ctypes\__init__.py", line 353, in __init__
    self._handle = _dlopen(self._name, mode)
WindowsError: [Error 5] Access is denied
>>> import os
>>> flam3_dll = CDLL(os.path.abspath('libflam3.dll'))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "c:\Python26\lib\ctypes\__init__.py", line 353, in __init__
    self._handle = _dlopen(self._name, mode)
WindowsError: [Error 5] Access is denied
>>>

Any ideas what would be causing this and better yet someway around it?

Answer 1

I know it sounds like a silly thing, but since you didn't explicitly mention it:

Did you check the permissions on the file you're trying to access? Perhaps you, you know, don't have read or execute access to the file.