Category Blog - Doesn't work - Fatal Error Message

Hi, I am trying to add a new menu item say "My Blog" under Navigation(front-end) which is under "Top Menu 1" at the back-end. My setting under Top Menu 1 --> My Blog --> Blog Layout, are below:
# Leading Articles - 0
# Intro Articles - 7
# Columns - 1

That means, under "My Blog" page I want to display 7 article per page horizontally with Read More link, with no leading article .

Once I save and go back to my main site and click on "My Blog" Nav it doesn't work and shows this error message:

Fatal error: Call to undefined method JHtml::core() in C:\xampp\htdocs\testsite\templates\hot_blocks\html\com_content\category\blog_item.php on line 18

Please help me to solve this problem. I need to fix this urgently.
Thanks in Advance

Do you use latest joomla , if not update. If you cannot save settings in back-end that can not be caused by template instead it indicates your joomla core is damaged. Also better ask on joomla forum because that is their teritorry

Hi Ivan, Thanks for your quick reply. I do not have any problem with saving setting at the back-end, it seems everything is fine at the back-end and I've already updated to joomla version 3.2.1. Still same problem. Any other idea? Oh! I just did a fresh installation too. Still same problem! If you don't mind could you please check on your template if you can achieve, what I am trying to achieve here.

I believe the problems is with the Template not with Joomla Core. Check on this file under the -
templates -->hot_blocks-->html-->com_content-->category-->blog_item.php

Thanks in advance

Rename:

templates\hot_blocks\html\com_content\category\blog_item.php

to

blog_item.ph_

copy

components\com_content\views\category\tmpl\blog_item.php

to

templates\hot_blocks\html\com_content\category\blog_item.php

Hi Ivan thanks for your reply. I did try your solution before your reply, but that solution actually change the behaviour of article presentation such as - link image comes in middle, title goes on top and whole article becomes hoverable.

After studying the code I have found the simple solution! Which is , just open the file from
templates -->hot_blocks-->html-->com_content-->category-->blog_item.php

And from line 18 just delete JHtml::core( );

After this modification article presentation should work according to your template design. In my case I did achieve what I was trying to achieve.
Thanks for your help.