unable to create pdf

prawn (0.8.4)
prawn-core (0.8.4)
prawn-format (0.2.3)
prawn-layout (0.8.4)
prawn-security (0.8.4)

the above gem ive used for pdf
this is the error i get
NoMethodError in Employee#profile_pdf

Showing app/views/employee/profile_pdf.pdf.prawn where line #1 raised:

undefined method `header' for #<Prawn::Document:0xb6603d10>

Extracted source (around line #1):

1: pdf.header pdf.margin_box.top_left do
2: if FileTest.exists?("#{RAILS_ROOT}/public/uploads/image/
institute_logo.jpg")
3: logo = "#{RAILS_ROOT}/public/uploads/image/institute_logo.jpg"
4: else

RAILS_ROOT: /home/hanish/Honey/eabyasbio16dec
Application Trace | Framework Trace | Full Trace

/usr/lib/ruby/gems/1.8/gems/prawn-core-0.8.4/lib/prawn/graphics/
color.rb:72:in `method_missing'
/home/hanish/Honey/eabyasbio16dec/app/views/employee/
profile_pdf.pdf.prawn:1:in
`_run_prawn_app47views47employee47profile_pdf46pdf46prawn'
/home/hanish/Honey/eabyasbio16dec/app/controllers/
employee_controller.rb:623:in `profile_pdf'
/home/hanish/Honey/eabyasbio16dec/app/controllers/
employee_controller.rb:622:in `profile_pdf'

i used the pdf before wht is the error
thanks in advance