After installing NumXL, a few users have reported this error popping up when they open Excel.
The problem is directly related to the initialization of the user-interface portion of the Add-in and the virus scanner software on the user's machine. Nevertheless, the actual functions (e.g. ACF, WNTest, etc.) should be available and ready for use.
The problem occurs when the virus scanner on the client machine interferes with the add-in start-up code; We have seen this problem with Trend Micro Virus Scanner and AVG, and others may have similar issues.
To get around this problem, update your virus scanner software and/or add an exception to allow Excel (and NumXL) to access the system registry.
If you continue to experience this error, please contact our support line for further assistance.