These are the meta variables used generally with File Classes.
Both of the help us in defining the path of the file. One of them is Absolute and other one is Relative.
I will not go much details about the syntax of the functions which use these variables.
I believe most of you might have put this question to your self when encounterd with below variables like what is Absolute path and Relative path.
%FilePath_Absolute: We define the actual path on the server.
We can place file on any folder path in the server.
%Filepath_Relative: This uses the system defined path.
Files can be placed in the sub-folders beneath this path.
System Defined paths are like PS_FILEDIR/PS_SERVDIR etc.