The progress bar is not working in theme "gray" for iriver H120/H140 submitted in 2009 by Demetrios Stylianopoulos.
To fix this you need to add "%V(0,0,160,128,0)" just before line 18, which contains: "%pb(6,73,148,4,progressBar.bmp)" in file gray.wps.
Link to "gray" theme:
http://themes.rockbox.org/index.php?themeid=287&target=iriverh120