We have recently migrated from MOSS 2007 to MOSS 2010. The migration was successful. Unfortunately I have discovered we cannot access the workflows associated with the sites in SPD 2010. The workflows appear in SPD 2010 under List Workflows, but we get the error Unable to Load workflow action from the Server. We have looked into this error and have made sure the WSS.ACTIONS are well-formed. Is there anyone else who has had this problem?
After a view more days of researching, I tried a few things that were suggested. One of the solutions was to recycle the application pools and restart the timer service of the server. Doing this granted me access to the workflows when using the Prod URL in SPD 2010. Now the problem is I can not start a workflow using the Dev URL. If anyone else has had this issuse after migrating to MOSS 2010, I suggest recycling the app pools to see if it helps.
The problem ending up being different Applications versions. The user was trying to use SPD 2007 with SharePoint 2010.