You are using outdated DOpus version.
DOpus5 example:
Code:
IF sel = '' THEN f = 'FILES' /* All files */
ELSE f = 'SELFILES' /* Selected files */
'LISTER QUERY ACTIVE' ; activehandler = result /* Get handle of ACTIVE lister */
'LISTER QUERY' activehandler f 'STEM' filelist /* Store (selected) files of ACTIVE lister into stem variable */
For DOpus4 you may can use '0A'x as seperator if DOpus4 can handle it.