Error in Wordpress help me out

[sajiv]

hi i added tags in my blog,but when i click it shows the error like this,give me a right soltion 

Fatal error: Call to undefined function utw_showcurrenttagset() in /home/itacumen/public_html/sajiv/wp-content/themes/vistered-little/vistered-little/header.php on line 6 

[Sudhakar]

Is the problem still exists.

If yes, login to your blog admin page.

Deactivate the theme. 

And go to ftp manager. Remove the theme folder inside wp_content/wp_theme/theme_folder_name

And login to mysql and change the default theme to be 0.