Would you please confirm if you’re using SDK Source 2.6.31_09.12.01 (link below)? This is the latest official release from Freescale.
I would check if your host does have all the packages required and since the error appeared when building pot I would recommend double checking that the popt files are available. These should be part of the SDK source package (L2.6.31_09.12.01_SDK_source\pkgs\ popt-1.7.tar.gz)