The Nintex Workflow convert document action, allows you to convert documents such as Word, RTF, Web Pages and Word 2003 XML into PDF format. This action is only available with the Enterprise edition of Nintex Workflow and requires Word Automation Services be enabled and configured on your SharePoint 2010 environment.
Configuring Word Automation Services
Navigate to Central Administration and click on Manage Service Applications.
Scroll down and you'll find the Word Automation Services.
Click on the Word Automation Services. You'll be provided with settings you can update.
The important setting to make note of, is the "Conversion Throughput". By default, it's set to 15 minutes. This means that once you put in a request to convert a document, it takes between 1 amd 15 mins for the job to start.
To convert documents, you can simply add the Convert Document action to your workflow.
In order to test it out, I created a very simple word document to a Document Library and configured the Convert Dcoument action this way:
The above configuration creates a PDF in the same library the workflow is running in.
I haven't enabled the error handling for this test, but you could do this in case an unexpected error occurs and you want to make your workflow more robust.
Below you see that the workflow ran and within a minute, it created the PDF.
I haven't been able to generate errors with this action as yet, but if you do get some and you're not capturing errors, look in your SharePoint logs for "Workflow Infrastructure" error messages. It may help come to a conclusion as to the cause of the error.