Just for the record, in case anyone ever has the same problem - and we're all moving towards 64bit, so these problems may arise again.
PC, Vista Ultimate 64bit, 8gb RAM.
1. Photoshop appears to install the color drivers in C:\Windows\SysWOW64\SPOOL\DRIVERS\COLOR
...and not in the 32bit color drivers folder that it would normally install them in (e.g. in Windows XP Pro 32bit).
2. So, Flexcolor, as far as I can gather, can't "see" the drivers in the 64bit folder. It goes looking for them in the 32bit one.
3. Copying the drivers from C:\Windows\SysWOW64\SPOOL\DRIVERS\COLOR and pasting them into C:\WINDOWS\system32\spool\drivers\color doesn't work either because, for some weird reason, the file Type of the drivers is changed during the copying from .icc to _adbnew. No one knows what _adbnew is! Suffice to say that,
a. Flexcolor still can't "see" the drivers and....
b. If you right click on them, the option to 'Install Profile' does not appear.
4. So, what you have to do is to download and install a new set of drivers from here>http://www.adobe.com/digitalimag/adobergb.html
and install them. They are automatically installed in the 32bit color drivers folder and with the correct file type. i.e. .icc.
Only then will Flexcolor 'see' them!