If you've only got one piece of information to put into the page, why do you need a loop anyway? And, can you please show us your template or the relevant portion thereof? That error message isn't saying you've fed it the wrong thing, it's saying you're trying to set parameters but there's no parameter which has the same name as your hash key.

The basic structure of your loop and array should be something like this -- if you've got a page like this:

FIRSTNAME LASTNAME
---------------------
Fred      Flintstone
Barney    Rubble
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Then you need an array like this:

@loop_data = (
    { firstname => 'Fred',   lastname => 'Flintstone' },
    { firstname => 'Barney', lastname => 'Rubble' }
);
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and a template that looks like this:

FIRSTNAME LASTNAME
---------------------
<tmpl_loop name="foo">
  <tmpl_var name="firstname">
  <tmpl_var name="lastname">
</tmpl_loop>
[download]