The Cipher Challenge

I was reading a post on Hacker News from a company that is hiring. They were pretty smart about it. They did not give out their name or URL. Instead they made you work for it. The ciper text "xfbhlqtlj" was provided. You were told to decipher it using Vigenère decryption.

Oh yeah. You were also told to use the number 61803398874 from their URL. What? Anyone know what the heck Vigenère decryption is? Sure. Wikipedia does. This is a Caesar ciper with a varying shift. The number provided tells you how many characters each letter in the cipher text needs to be shifted.

I tried shifting them to the right. No luck. The result was mumbo jumbo. But when I shifted the letters to the "left" in the alphabet, I got their name. Bamm. Nice way to make me work for the URL. Too bad I am not in the running for any of their positions or their location.

Not sure why a C and python program would come up with different result while decrypting the text.