Redmine

We use redmine long time ago. Version: Redmine 1.2.1.stable (MySQL)
ruby: ruby-1.8.7-p334
rails: Rails 3.0.8

Since one month use a new editor:
Redmine CKEditor plugin 0.0.6 and use html table
When i copy a table to issue and make pdf from this issue, redmine said 500 Internal Server error.

From log:

Processing IssuesController#show to pdf (for 109.61.100.158 at 2012-10-18 17:06:19) [GET]
Parameters: {"format"=>"pdf", "action"=>"show", "id"=>"5401", "controller"=>"issues"}

NoMethodError (undefined method `size' for nil:NilClass):
lib/redmine/export/pdf.rb:119:in `RDMwriteHTMLCell'
lib/redmine/export/pdf.rb:393:in `issue_to_pdf'
lib/redmine/export/pdf.rb:379:in `each'
lib/redmine/export/pdf.rb:379:in `issue_to_pdf'
app/controllers/issues_controller.rb:125:in `show'
app/controllers/issues_controller.rb:121:in `show'
dispatch.fcgi:23

Rendering /var/www/sites/aion.hu/doc/redmine1.2.0/public/500.html (500 Internal Server Error)