libname xls pcfiles Error

[Harsh11387]

libname xls pcfiles path="&dispout."; 

	proc sql noprint;
		drop table xls.DispositionANew,
                   xls.DispositionBNew, 
				   %if &ds_tte. %then %do;
				    %do a = 1 %to &num_dsd.;
					 xls.Sheet&a.,
					 xls.Sheet&a.E,
				    %end;
				   %end;
	               xls.Info
                   ;
	quit; 


	data xls.DispositionANew;
		set final_dispositionA;
	run;

For above SAS code, I am getting an error while reading excel files(.xls) files. As we have excel files into .xls format so we can't change engine to "XLSX". Currently I am using SAS v9.4 for running code. Kindly see below snippet of error.

Any suggestions would be appreciated to fix this code. 

ERROR: Unable to locate pcfserver.exe. Please install PC Files Server.
ERROR: Error in the LIBNAME statement.
ERROR: Libref XLS is not assigned.
WARNING: Table XLS.DispositionANew has not been dropped.
ERROR: Libref XLS is not assigned.
WARNING: Table XLS.DispositionBNew has not been dropped.
ERROR: Libref XLS is not assigned.
WARNING: Table XLS.Sheet1 has not been dropped.
ERROR: Libref XLS is not assigned.
WARNING: Table XLS.Sheet1E has not been dropped.
ERROR: Libref XLS is not assigned.
WARNING: Table XLS.Sheet2 has not been dropped.
ERROR: Libref XLS is not assigned.
WARNING: Table XLS.Sheet2E has not been dropped.
ERROR: Libref XLS is not assigned.
WARNING: Table XLS.Sheet3 has not been dropped.
ERROR: Libref XLS is not assigned.
WARNING: Table XLS.Sheet3E has not been dropped.
ERROR: Libref XLS is not assigned.
WARNING: Table XLS.Info has not been dropped.

[PaigeMiller]

ERROR: Unable to locate pcfserver.exe. Please install PC Files Server.

What does macro variable &DISPOUT resolve to? 

[Harsh11387]

/* location and filename of the output */
	%global outfile outpath;
	%let outpath = &top_dir.\Outputs;
	%let outfile = Disposition.xls;

	%global dispout errout;
	%let dispout = &outpath.\&outfile.;	

Please see above mention code for macro variable resolution.