Use of GHC's environment variable GHC_PACKAGE_PATH is incompatible with Cabal.

[heath]

An attempt to install a package:
https://gist.github.com/heath/5680419

Use of GHC_PACKAGE_PATH within sandboxer.sh:
https://github.com/lightquake/sandboxer/blob/master/sandboxer.sh#L40

Is this the line you recommended commenting out in the README?