我相信这是因为我使用SciPy安装了python，所以显然它不在psycopg2安装程序所在的注册表中。无论如何修复此问题而不在现有安装上安装python26？我不确定这是否会破坏它。
编辑：我的PYTHONPATH如下所示：
'C:\\Python26\\scripts',
'C:\\Python26\\lib\\site-packages\\apptools-3.3.0-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\blockcanvas-3.1.0-py2.6-win32.egg',
'C:\\Python26\\lib\\site-packages\\chaco-3.2.0-py2.6-win32.egg',
'C:\\Python26\\lib\\site-packages\\codetools-3.1.0-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\configobj-4.6.0-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\enable-3.2.0-py2.6-win32.egg',
'C:\\Python26\\lib\\site-packages\\enthoughtbase-3.0.3-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\envisagecore-3.1.1-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\envisageplugins-3.1.1-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\ets-3.3.0-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\etsdevtools-3.0.3-py2.6-win32.egg',
'C:\\Python26\\lib\\site-packages\\etsprojecttools-0.5.1-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\mayavi-3.3.0-py2.6-win32.egg',
'C:\\Python26\\lib\\site-packages\\scimath-3.0.4-py2.6-win32.egg',
'C:\\Python26\\lib\\site-packages\\setupdocs-1.0.3-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\traits-3.2.0-py2.6-win32.egg',
'C:\\Python26\\lib\\site-packages\\traitsbackendqt-3.2.0-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\traitsbackendwx-3.2.0-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\traitsgui-3.1.0-py2.6.egg',
'C:\\Python26\\lib\\site-packages\\python_twitter-0.6-py2.6.egg',
'C:\\Program Files (x86)\\OpenLibraries\\python',
'C:\\Python26\\python26.zip',
'C:\\Python26\\DLLs',
'C:\\Python26\\lib',
'C:\\Python26\\lib\\plat-win',
'C:\\Python26\\lib\\lib-tk',
'C:\\Python26',
'C:\\Python26\\lib\\site-packages',
'C:\\Python26\\lib\\site-packages\\PIL',
'C:\\Python26\\lib\\site-packages\\win32',
'C:\\Python26\\lib\\site-packages\\win32\\lib',
'C:\\Python26\\lib\\site-packages\\Pythonwin',
'c:\\python26\\lib\\site-packages',
'C:\\Python26\\lib\\site-packages\\wx-2.8-msw-unicode',
'C:\\Python26\\lib\\site-packages\\IPython/Extensions',