[tex-live] Portable install: `Failure to execute command'

[Siep Kroonenberg]

I tried a usb install of TL2011 for a colleague. I could install the
tray icon in the system tray, and I could run the TL console, but I
could not run any other programs: gui programs produced a messagebox
`Failed to execute command: ...' and command-line programs produced
a similar message in spanish. This problem was specific to the
machine, not to the usb stick: another usb stick failed similarly on
this machine, and neither usb stick failed on a couple of other
Windows systems.

I ended up doing a regular install of TL2010, which worked fine.

I realize that this is not enough information for debugging, and I
currently don't have access to his laptop either, so I just ask
whether this rings a bell to any Windows user?

-- 
Siep Kroonenberg