Here you go, compare the checksums on your downloads with these, they're from the primary link on calibre download pages - I've installed 4 64-bit, and 3 32-bit Version 2.1 from these msi's - all working OK.
64-bit
Code:
CRC32 a61b3382
MD5 2f430658f0f2fb3321d2fce72a37a35c
SHA-1 f6960bd42c234d2aab5d971953852f6134f45644
SHA-224 512d15b045872c7ac088764315b6448439fae3a47f7dda5098fd2913
SHA-256 fe466a6d897b5abd1cd811b21f6f47808755e15426961967e438546926b1eeaf
SHA-384 d81c51e5ae44669588a7b6014947012e237a70a3c11c5b9212ff7504e4b3f3344f88d18aa960fcc06f82fc0761455bdc
SHA-512 b86f751fc93ac900153fae53fd660462fcaa85f80145fb3981924188819bacb967e0b57b6c76c772314bbaa47f10c7f23eeeaa9c35c7f935fcd792a9f1ee6899
32-bit
Code:
CRC32 2f7934f1
MD5 007f2218d9cd7c28c71900e60747e8fa
SHA-1 d2491d23d8f4ec89e6ad695ad433f4a48009667c
SHA-224 a1b1c0718ef42c576ec6a5446fdcdc6c867e290e21f6ad12821f8071
SHA-256 ccea7227f77c968fb03c9b462fca39f4cab97ca95307d21e22b3d20aae4658d8
SHA-384 b79f24cf8ffb6e165ebb327d937775ca9b410011be9f535107dea1c670f9474d97819bd162cc6e6c6951f7f8ab3b952e
SHA-512 8c860debdc94b5c00e0c922d8ce9a0854608b2069bd6ae6c9cc352c332babf6885a3c3d13f36e15af7e8320cefe0dc3578908cc6573ba6cc32a71803aa7bd40b
Added : These are the Revision Identifiers from the Property Detail sheets
64 bit Revision Number {533D06A4-F371-4064-8C0B-43E774AE5DAD}
32 bit Revision Number {DABA1E93-1060-4E33-8B55-972C8DA07470}
BR