After starting IE9-WindowsVista-x64-enu.exe Playonlinux.log went inediatly to 25GB until the free space of my harddisc was empty. after removing the logfile my space came back.
So I linked playonlinux.log to /dev/null
but now whil the second run the free space also disapear but I do not know where this file is, because the size of playonlinux.log is 0kb. "Disk Usage Analyzer" is not able to show me the Location of the wasted diskspace.