TypeError in Projects#show

Showing /app/app/views/projects/show.html.erb where line #322 raised:

nil can't be coerced into Float
Extracted source (around line #322):
320
321
322
323
324
325
              
total vol (qty: <%= @project.quantity %>)[mm^3]:
<strong>
<%= number_with_precision(stlParameters[4]*@project.quantity, :precision => 2) %>
</strong>
</div>
</div>

Rails.root: /app

Application Trace | Framework Trace | Full Trace

Request

Parameters:

{"id"=>"hjh"}

Response

Headers:

None