I\'m running Mac OS 10.6.8. and wanted to install in addition to python 2.6 also python 2.7 and use python 2.7 in a new virtualenv. I executed the following steps:
I
Try to uninstall your virtualenv and virtualenvwrapper and install it again using pip in version 2.7 (I think).
virtualenv
virtualenvwrapper
pip
I encountered the same error and I just did this and solved my problem.
I using U