With arexx or dos you can't find the path of your prog.
You must get it to load external resources in your prog, for example.
Searchprogdir help to find it.
If you have install searchprogdir in your maindir of your prog, you must only execute it at start of the prog. Then                     
it install a "searchprogdir:" - assign. to your actual progdir. 

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                15762   39940  39.5% -lh5- 33f4 Jan  2 15:05 searchprogdir/searchprogdir
[generic]                  300     551  54.4% -lh5- 1fc2 Jan  2 14:58 searchprogdir/searchprogdir.readme
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         2 files   16062   40491  39.7%            Jan  2 17:53