an indirect answer:
I have quickly double checked your data with some of my scripts. The replacement of the transaction and the created double hash value seems to be correct. I am not understanding the pubkey you use in the function main().

When I am using the pubkey of the pubkey script you extracted (of course without the length field and without hex "ac" at the end), then it runs ok.

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using the reference from here: http://bitcoin.stackexchange.com/questions/46455/ I get this result:  

pubkey in HEX: 04b0bd634234abbb1ba1e986e884185c61cf43e001f9137f23c2c409273eb16e6537a576782eba6 68a7ef8bd3b3cfb1edb7117ab65129b8a2e681f3c1e0908ef7b
pubkey in PEM format:
-----BEGIN PUBLIC KEY-----
MFYwEAYHKoZIzj0CAQYFK4EEAAoDQgAEsL1jQjSruxuh6YbohBhcYc9D4AH5E38j
wsQJJz6xbmU3pXZ4Lrpmin74vTs8+x7bcRerZRKbii5oHzweCQjvew==
-----END PUBLIC KEY-----

sha256: f27c6c3aa42563c958292922be1e53fe107f4db0dfadba11122f0b12bf77f3ab

ScriptSig:     3044022014d647cd08f1ea5b31d1e6539b6cbceb9182f6e7b2e29fb969354ef7e3434923022028b b4eda36af410149baa936322e7c0e46cc5540a3aa89c811bc3c360028bfd3

*** Signature Verified Successfully ***