Hi:
  As Paige suggests, seeing your LOG would be most helpful. One suggestion...are you sure that your E drive is available??? For example, review this SAS log:
[pre]
192  %let data_folder = e:\;
193  libname test "&data_folder.";
NOTE: Libref TEST was successfully assigned as follows:
      Engine:        V9
      Physical Name: e:\
                                      
194  %let data_folder = j:\;
195  libname test "&data_folder.";
NOTE: Library TEST does not exist.
        
[/pre]
 
 On my windows system, I DO have an E: drive, but I do NOT have a J: drive. 
 
  As a general rule of thumb, it is a bad idea to "pre-quote" your macro variables in the %LET statement. Macro variables are just character strings and quotes belong in the statements where you USE the macro variables.
 
  For example in these two %LET statements below the second (unquoted) value for 16 is the correct usage:
[pre]
%let age = '16';
%let age = 16;
[/pre]
                                                                       
 As you can see from this LOG, with quotes inside &AGE, my WHERE statement is incorrect:
[pre]
196  %let age = '16';
197  proc print data=sashelp.class;
198    title "1) Wrong: Students who are &age";
199    where age = &age;
ERROR: WHERE clause operator requires compatible variables.
200  run;
                 
NOTE: The SAS System stopped processing this step because of errors.
NOTE: PROCEDURE PRINT used (Total process time):
      real time           0.01 seconds
      cpu time            0.00 seconds
201
202  %let age = 16;
                   
203  proc print data=sashelp.class;
204    title "2) Right: Students who are &age";
205    where age = &age;
206  run;
                
NOTE: There were 1 observations read from the data set SASHELP.CLASS.
      WHERE age=16;
NOTE: PROCEDURE PRINT used (Total process time):
      real time           0.18 seconds
      cpu time            0.03 seconds
                                                                      
[/pre]
                                                                         
This paper is a good introduction to Macro processing concepts. 
http://www2.sas.com/proceedings/sugi28/056-28.pdf
              
cynthia