Again, the problem is most likely NOT with any of those file but because you've modified the 16F877.BAS file by adding your actual program code to/in that file. Because of this the compiler tried to include the needed support files (PIC14EXT.BAS and PBPPIC14.RAM) TWICE which is what causes the Redefinition of VAR error.

So again, restore the 16F877.BAS to its original state and keep your program code in a file (or files) of its own.