I just purchased a copy of your tool, and I'm getting the error
when I try to export using your tool.
If you have Outlook (not Outlook Express as it is not supported) installed on the PC
The next step is to make sure it to set to the default mail client.
You can do this in Internet Explorer.
From menu, Tools - Internet Options - Programs tab
Email must say Microsoft Outlook. If it already does change it and save then change it back to Microsoft Outlook and save again. Sometimes with automated installs people neglect to update all the necessary registry settings. This should set them corectly.
Please let me know how it goes after that.