try

lcFile = "Tst.txt"
= strtofile(m.lcmd, m.lcFile, 0)
FOR m.li = 0 TO m.liNumDesc-1
    * m.lcmd = m.lcmd + ["] + oChildNode.ITEM(m.li).TEXT + [",]
   = strtofile( ["] + oChildNode.ITEM(m.li).TEXT + [",], m.lcFile, 1)
ENDFOR

as this eliminates the heavy memory copies as the string grows.

HTH

thomas