Then the private key you are trying to sweep is not for address: 1Hefr1NLzABVZhK9Kh7XSB55xRFtK5ex6e
Just confirm that your private key starts with a "5" or a "K" or an "L"??... DO NOT post your private key here!

It's possible that this might be a compressed/uncompressed key issue... Very unlikely, but you never know... I'd suggest that you try using an offline copy of
www.bitaddress.org and on the "details" tab, pasting in your private key and seeing what addresses it actually generates.
If you see the "1Hefr" address shown, then double check that the associated private key in WIF format is the one you're actually trying to sweep