Update: Nintex have resolved the issue with lightning speed. A new version of NW2010 (18.104.22.168) is_** available for download with immediate effect.
It has recently come to our attention that the new version of Nintex Workflow 2010 (v22.214.171.124) released at the end of March 2011 contains a breaking change in the Nintex API. As a result users will get an error message when opening any workflows in the NW2010 Designer that contain the Muhimbi ‘Convert to PDF’ workflow action. The workflow will continue to work just fine, it is just not possible to amend it.
The exact error message you will see when opening the Nintex Workflow Designer is as follows:
Error retrieving config xml for activity 'Convert file to PDF' using adapter type Muhimbi.SharePoint.DocumentConverter.Nintex.PDFConverterAdapter, Muhimbi.SharePoint.DocumentConverter.Nintex, Version=126.96.36.199, Culture=neutral, PublicKeyToken=c9db4759c9eaad12
We are currently working with Nintex to see if they can issue a patch. In the meantime our advice is to use Nintex Workflow 2010 188.8.131.52. If you have already upgrade to 184.108.40.206 and cannot revert back to 220.127.116.11 then please contact us for a workaround.
Please note that this issue does not affect Nintex Workflow 2007.