[Rails] 0.10 upgrade problem

Sat Feb 26 22:30:52 GMT 2005

I'm having problems with the upgrade to 0.10.0

I get the following error on all my applications

  NoMethodError in  Heatmap#display

  Showing /heatmap/display.rhtml where line #11 raised  undefined method 
`each_with_index' for nil:NilClass
8:   <body><font size = "2">
9:      <table border="2">
10:             <tr>
11:     <% @arr.each_with_index do |h, i| %>

I've followed the instructions on upgrading at  
http://manuals.rubyonrails.com/read/book/15

Any ideas what I'm doing wrong. 