How to install a component for Joomla 1.0.x to 1.5
Joomla 1.5 has a built-in "legacy" plugin which allows extensions that are not compatible with 1.5 to be installed.
You can enable this plugin from your Joomla admin area -> Extensions -> Plugin Manager. In the Filter: field type Legacy and click on Go. The System-Legacy plugin will appear below. To enable it, simply check the box next to it and then click the Enable button located at the top-right Joomla menu.
However, we would advise you to use components which are fully compatible with Joomla 1.5 in order to avoid any discrepancies and malfunctions in your Joomla application.
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