Autocad2011: Error installing SP1 for Autodesk Navisworks

When attempting to install SP1 for your Autodesk Navisworks 2011 product you receive the error:
"Error 1402. Could not open key"

Solution

The cause of this issue is related to a key held by the Navisworks exporters.  To resolve this issue, a temporary removal of the exporters should help. Here are the steps:

1. Access the Add/Remove Programs option from your Control Panel.
2. Click on 'Autodesk Navisworks 2011 32/64 bit Exporter Plug-ins' (NOT the Language Pack option).
3. Click the 'Uninstall/Change' button.
4. Click 'Add or Remove Features' option.
5. UNCHECK ALL of the checked options.
6. Click 'Next' and follow the prompts to remove the exporters.
7. Once the exporters are removed, install Service Pack 1 for your Autodesk Navisworks 2011 product.
8. After the Service Pack is installed, access the Add/Remove Programs option from your Control Panel.
9. Click on 'Autodesk Navisworks 2011 32/64 bit Exporter Plug-ins' (NOT the Language Pack option).
10. Click the ' Uninstall/Change' button.
11. Click 'Add or Remove Features' option.
12. Click 'Restore Defaults' to automatically check the appropriate options.
13. Click 'Next' and follow the prompts to install the exporters.

If this process does not correct the issue, remove the exporters completely. This process requires you to have the original installation files or to download the installers from the Autodesk website. 
Here are the steps:

1. Access the Add/Remove Programs option from your Control Panel.
2. Click on 'Autodesk Navisworks 2011 32/64 bit Exporter Plug-ins' (NOT the Language Pack option).
3. Click the ' Uninstall/Change ' button.
4. Click 'Uninstall' and follow the prompts to uninstall the exporters.
5. Once the exporters are removed, install Service Pack 1 for your Autodesk Navisworks 2011 product.
6. After the Service Pack is installed, install the exporters.