windows boot manager install failed

[skobus]

The plop boot manager served me well on my 2003 laptop because that did not have a USB boot option in the bios.
Unfortunately I had to reinstall windows XP and after some problems the new installation ended up in partition F.
No big deal, everything works fine with F as systemdrive. The F partition is the active partition, ntldr and boot.ini are in the root of F and there is no C partition anymore.
I installed the plop boot manager in the windows boot menu (XP) with InstallToBootMenu.bat. There were no errors and the plop entry showed up in boot ini. But on choosing it I got an error:

Windows could not start because of a computer disk hardware configuration problem.
Could not read from the selected boot disk. Check boot path and disk hardware.
Please check the Windows documentation about hardware disk configuration and your hardware reference manuals for additional information.

Apparently plpbt4win.ldr cannot be found. When checking with plpbt4win.exe, the loader and bin file are specified in c:\plop (which does not exist).
Manually specifying the directories in plpbt4win seems to work, initially the F drive is shown (f:\plop is the directory), but on closing and re-opening plpbt4win, the loader and bin file are shown in c:\plop (which does not exist). So it looks like the %systemdrive% variable is not correctly handled.
Any ideas?