A quick fix to it .
Here I am using fishpig extension .
Observed that fishpig is overridding magento core sitemap controller .
So added the following code : /app/code/community/Fishpig/Wordpress/controllers/Adminhtml/SitemapController.php
Add this code before :
$this->_redirectReferer();
$id = $this->getRequest()->getParam('sitemap_id');
$sitemap = Mage::getModel('sitemap/sitemap');
/* @var $sitemap Mage_Sitemap_Model_Sitemap */
$sitemap->load($id);
// if sitemap record exists
if ($sitemap->getId()) {
try {
$sitemap->generateXml();
$this->_getSession()->addSuccess(
Mage::helper('sitemap')->__('The sitemap "%s" has been generated.', $sitemap->getSitemapFilename()));
}
catch (Mage_Core_Exception $e) {
$this->_getSession()->addError($e->getMessage());
}
catch (Exception $e) {
$this->_getSession()->addException($e,
Mage::helper('sitemap')->__('Unable to generate the sitemap.'));
}
} else {
$this->_getSession()->addError(
Mage::helper('sitemap')->__('Unable to find a sitemap to generate.'));
}
Hope it helps someone experiencing with same issue .
Courtesy : lukecollymore