Error message when you try to open the Purchase Order Entry window in Purchase Order Processing in Microsoft Dynamics GP 10.0: "You don't have security privileges to open this window"

Symptoms
When you open the Purchase Order Entry window in Purchase Order Processing you receive the following error message:
You don’t have security privileges to open this window. Contact your system administrator for assistance.
If you grant access to the Purchasing Agent user, the Purchase Order Entry window opens.
Cause
This problem occurs because an additional resource for another add-in module needs security granted. For example, Manufacturing is the most common resource that is installed and that needs security granted.
Resolution
To resolve this problem, use one of the following methods.
Grant access to the ECM_DPOP_Hidden window
Note The following steps assume that Manufacturing is the resource that causes the problem.

1. On the Microsoft Dynamics GP menu, point to Tools, point to Setup, point to System, and then click Security Tasks.
2. In the Security Task Setup window, specify the following fields:
   • Task ID: Enter a task that is assigned to the user
   • Product: Manufacturing
   • Type: Windows
   • Series: 3rd Party
3. In the Access List section, click to select the Hidden check box to grant access to the ECM_DPOP_Hidden window.

1. On the Microsoft Dynamics GP menu, point to Tools, point to Customize, and then click Customization Status.
2. In the Customization Status window, select one of the add-in products or one of the third-party applications, and then click Disable to temporarily disable the product or the application.
3. Try to open the Purchase Order Entry window.
4. Repeat step 1 through step 3 to determine which add-in product or third-party application causes this problem.