firefox portable 2.0.0.5_en-us

I have two devices. On one, I moved the existing firefox directory to FirefoxPortable.dec under the PortableApps. I added the new Firefox instance.

from my laptop, I was able to login, set preferences, install add-ons to the portable hard-drive.

Accessing the drive, via a permissions restricted Customer Site PC (Windows 2000), there was a message indicating that the security component would not initialize. Tracking down the error message indicated that it was trying to open profiles from under the C:\Document and Settings.
Obviously a mistake. ? how does the local firefox instance know to find the profile under the firefoxPortable directory?

by contrast the firefox instance in the earlier directory (from 2.0.0.3) installed from PortableApps last December, works correctly on the same machine. it finds and only uses the profile in it's installation. (which i think is the normal behavior)

The new release appears to have problems identifying the location of the user profile (a problem not seen with the prior launcher)

is there an config option or about:config option that sets the profile location?