This problem is caused by a mis-configuration in Internet Explorer.
If you are using Internet Explorer 4.01, the following procedure should solve the problem:
- Click Start, click Run, and then type regsvr32 mmefxe.ocx in the Open box.
- Click OK, and then click OK when you receive the "DllRegisterServer in mmefxe.ocx succeeded" message.
The original Microsoft Knowledge Base article about this can be found at http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q223331.
If you have version 5 or greater of Internet Explorer, we have found that simply re-installing Internet Explorer solves the problem.