Craft\InstaBlogPlugin::onBeforeInstall PHP Method

    public function onBeforeInstall()
    {
        $craftTemplateFolder = realpath(CRAFT_TEMPLATES_PATH);
        if (!IOHelper::isWritable($craftTemplateFolder)) {
            throw new Exception(Craft::t('Your Template folder is not writeable by PHP. ' . 'InstaBlog needs PHP to have permissions to create template files. Give PHP write permissions to ' . $craftTemplateFolder . ' and try Install again.'));
        }
        $sources = craft()->assetSources->getAllSourceIds();
        if (empty($sources)) {
            throw new Exception(Craft::t('You don\'t have any asset sources set up. ' . 'InstaBlog needs an asset source to be defined. Please create an asset source ' . ' and try Install again.'));
        }
    }