Edit: it looks like its an blockchain.info export format. Im not familiar with that format, maybe someone else can chime in. It might have some time to see if I can find a solution with some test keys.
Yep. Blockchain.info
in their infinite wisdom has abandoned the more traditional representations of bitcoin private keys (such as WIF and HEX) and instead decided to display private keys as a base58 value with no version, checksum, or compression indicators. I'm sure someone over there probably thought it would be a good idea, but I don't know why.
Therefore it seems that anyone running the latest blockchain.info web interface doesn't have access to the more traditional and multisystem-compatible formats. I'm sure there will soon be several converters written to help people with this problem.