Follow these steps in order until the issue is resolved:
  1. In the Enter /SiteID field, type your Site ID
    Note:  Make sure to leave the "/" in the field so your site ID should look like /5740
  2. Click Go
  3. Browse to C:\Windows\system32 directory and locate the webfldrs.msi file 
  4. Double-click the file and complete the installation wizard
  5. If the issue is not resolved, right-click the file and select Uninstall
  6. Re-install webfldrs.msi
For more information, review How to set up and access the Blackbaud Hosting Services Files Folder.