My first bet would be a missing/extra quote somewhere.

... could be an extraneous opening parenthesis.

#!/usr/bin/perl

({

  sub add_login{

      my ($var) = @_;
      #...
  }

}
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At least, this produces a rather similar error:

$ perl -c <629906.pl 
syntax error at - line 5, near "sub add_login"
Can't use global @_ in "my" at - line 7, near "= @_"
- had compilation errors.
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