This happens when clients machines are running Windows 7 OS and they have changed the default text size. (Note, this feature is also available in Windows 8, but no reports involving Windows 8 at the time of this article)
The default text is defined in Windows as Smaller (100%) When users change this to Medium or Larger, it effects the display in IQdesktop. To get the import button to reappear, change the size by right-clicking the desktop and choose 'Screen Resolution' and select the 'Make text and other items larger or smaller' link. You can also find this location in Control Panel > All Control Panel Items> Display.