Default Please help. My Samsung galaxy s2 skyrocket can't flash roms.

Please I'm looking for who to help me out. My Samsung galaxy s2 AT&T skyrocket sgh-i727 cant flash custom roms. When i'm trying to flash custom rom, it will abort and write "install zip aborted, this is a hercules". I've tried about 4 roms no avail. I'm on embryo 6 (4.1.2). I will be grateful to whoever is willing to help me out. Thanks.

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