I am developing a Python Toolbox that uses a few external libraries (ogr/gdal, matplotlib, shapely, reportlab among others) which files I have directly copied in the same folder as my toolbox .py, as recommended in Esri's A simple approach for including 3rd party Python libraries with your scripts. It works just fine on my computer, but when I run this tool on another computer, I get an ImportError. It's very likely that the libraries are the reason for that error.

<type 'exceptions.ImportError'>: DLL load failed: The specified procedure could not be found.

Moreover, I don't get the ImportError the same way from ArcGIS10.0 or ArcGIS10.1 (10.0: only get the error without any additional message; 10.1: get the error where it worked fine in the previous version), which worries me a bit because this really looks like a singular configuration dependent problem.

How do I find the missing dependencies in my current distribution and ensure that the tool which I distribute will work on every computer with a fresh ArcGIS installation?

I have tried what I consider the usual ways to solve that problem:

1 Answer 1


I don't think this is a matter of missing dependencies, it's a matter of incorrectly versioned dependencies. ArcGIS 10.0 runs Python 2.6, while 10.1 runs 2.7. Any library with a C extension will need to be bundled with your toolbox for the correct version of Python depending on the target version of ArcGIS.

  • Thanks, that's probably what explains the differences between the 2 versions. It makes me wonder something else: will the error be the same for a missing library and for an incorrectly versioned one? I will explore that. However I still have this ImportError occurring on other computers but not on mine (with the same version).
    – 7hibault
    Jul 2, 2014 at 13:07
  • You'll get the same error type (ImportError) but the error message will be different. Jul 2, 2014 at 13:12
  • Alright, that answers one problem. Do you have any additional insights on the missing libraries (or else if I'm wrong) issue?
    – 7hibault
    Jul 2, 2014 at 14:42
  • In your script tools, you may need to add the directory of the current script to sys.path so Python can find your bundled copies. Jul 2, 2014 at 15:09
  • Thanks for the suggestion but unfortunately it did not work (it didn't change the outcome at all)...
    – 7hibault
    Jul 8, 2014 at 12:05

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