NoMethodError in Tags#show

Showing app/views/tags/show.rhtml where line #5 raised: 

You have a nil object when you didn't expect it!
The error occurred while evaluating nil.name

Extracted source (around line #5): 

2: 
3:   <div id="breadcrumb">
4: 
5:     <h1><a href="/">Home</a> / Tag <%= @tag.name %></h1>
6: 
7:   </div> <!-- breadcrumb -->
8:

RAILS_ROOT: /var/www/rikkus.info/config/..

Application Trace | Framework Trace | Full Trace 
#{RAILS_ROOT}/app/views/tags/show.rhtml:5:in `_run_rhtml_47app47views47tags47show46rhtml'
/usr/bin/mongrel_rails:16:in `load'
/usr/bin/mongrel_rails:16

Request

Parameters: {"format"=>"html", "id"=>"mssql"}

Show session dump

Response

Headers: {"cookie"=>[], "Cache-Control"=>"no-cache"}