Adobe After Effects CS5 requires a 64-bit operating system.
No x86 version

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http://extabit.com/file/2a0p8e0phb2a1/Adobe After Effects (CS5).part1.rar
http://extabit.com/file/2a0p8e0phaz6x/Adobe After Effects (CS5).part2.rar
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http://extabit.com/file/2a0p8e0phaz95/Adobe After Effects (CS5).part5.rar