Generally you'd want PDM to be ahead of Solidworks in version, but I would bet you need to update the task.
You will also need to update the Solidworks addin and convert tool. This is from the knowledge base, but here are the steps:
If using an old version, upgrade the existing task add-in in the vault:
1. Open administration tool on an upgraded client log in as administrator
2. File > open > browse to c:\program files\solidworks enterprise pdm\default data\
3. Load the "Convert_GB.cex" file
4. Drag-and-drop SWTaskAddIn to the add-ins node (not the convert task). Select Yes to update the existing add-in. (see attached UpdateTaskAddin.jpg)
5. Verify via the task host configuration that the updated add-in is loaded
6. On clients that act as task host it is recommended to exit Enterprise and log in again to the view to ensure the updated add-in is loaded.
Once the add-in is upgraded you may need to update the actual task script as well. Refer to KB solution S-057908 for more details.
Note that this also applies to other add-ins in an upgraded vault, such as Dispatch. Those can be updated using the add-in node.
This is an easy task to do, don't sweat it!
~Corey Hinman, CEPA
Just wondering how does that affect the users that are still running 2011?