What version? Look at the bottom-left of the window.
From the Export menu toolbar, press the LOSSLESS button. If that's accepted, it may be the cure. Or...
Install the current release and see if that takes care of it.
For licensed users upgrades are free for up to six months from purchase date. After that, VP will continue to fully function but a fee will be required in order to register the newest. Retain your old install file and registration info.