When PlanGuru is installed we try to provide all the files we need to interface with QuickBooks, per Inuit's instructions. When this error message is received PlanGuru cannot communicate with QuickBooks as one of the requisite QB files was not installed on your machine.
You will need to download and install the QuickBooks supplied communications software from our website at http://www.planguru.com/ftpupdates/QBFC10_0Installer.exe. Download the file to your desktop and double-click to install. Once you've installed this file, you should be able to import from QuickBooks.