I'm not sure how this happened, but now I'm seeing that instead of a sidebar on my blog, I have a sliver of my blog header and the following error text running below it:

Smarty error: [in mt:172 line 4]: syntax error: unrecognized tag 'mtfeed' (Smarty_Compiler.class.php, line 580)

Not sure how this happened or what I need to do to fix it. Plus, I'm not very tech-savvy (as you can probably tell). Help!

Greg