first, the obligatory :

# perl -wT
# ^ whatever executable's appropriate!
use strict;
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Also, this chunk probably doesn't do what you want :

  if (param) 
  {
    $user_name = em(param('name'));
    &file_creation($user_name);
  }
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It checks to see if any parameter exists, then assumes that the name param will. that's bad.
Assuming a user name of "Jim", the next line assigns <em>Jim</em> to $user_name, and that's probably not what you want.