I think the problem is not cperl-mode, it looks more like you have yasnippet installed and binded to the TAB key, try disabling yasnippet ( or even uninstalling it ). With M-x yas/minor-mode-off

In reply to Re: Emacs: How to disable expansion of cperl-mode ? by bluescreen
in thread Emacs: How to disable expansion of cperl-mode ? by Anonymous Monk

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