Not Enough Breakpoints on the PIC16F1718
For the PIC16F1718 and many other small devices, the resources on the device only allow for a single hardware breakpoint. There are Emulation Headers available that provide additional hardware breakpoints.
For more information, read chapter 3, "Emulation Header List" and section A.3 of the same chapter, "Hardware Breakpoint Issue" in the "Emulation Extension Pak (EEP) and Emulation Header User's Guide", which lists all the individual headers available and a few workarounds.