You are receiving the Duplicate Layer error in Parlay because you or another user has added an additional Parlay License Key to the Place box in Google Earth and the number of allocated keys for your company has been exceeded. This often happens when a company has more than one user but can certainly happen to a single user.
To fix this, have each user review their layer tree in the Places window, and remove all but one copy of the Parlay Parcels layer tree from their copy of Google Earth. Right click on PARLAY Parcels in blue and select delete, then restart Google Earth. This should fix the issue.