how to enable template path hint in magento 1.4

If you want this option displayed for ‘default config’ also, just edit the app\code\core\Mage\Core\etc\system.xml file.
Look for something like this

<template_hints translate="label">
<label>Template Path Hintslabel>
<frontend_type>selectfrontend_type>
<source_model>adminhtml/system_config_source_yesnosource_model>
<sort_order>20sort_order>
<show_in_default>0show_in_default>
<show_in_website>1show_in_website>
<show_in_store>1show_in_store>
template_hints>

replace

<show_in_default>0show_in_default>

with

<show_in_default>1show_in_default>

Do the same for this section

<template_hints_blocks translate="label">
<label>Add Block Names to Hintslabel>
<frontend_type>selectfrontend_type>
<source_model>adminhtml/system_config_source_yesnosource_model>
<sort_order>21sort_order>
<show_in_default>0show_in_default>
<show_in_website>1show_in_website>
<show_in_store>1show_in_store>
template_hints_blocks>

and clear the cache