GNAT on a multiboot computer

[Anders Wirzenius <anders@no.email.thanks.invalid>]

Hi,

Does anyone have a good advice on how to set up the
GNAT compiler system on a multiboot Windows computer?

<context>
I have a multiboot computer (Win XP, Linux Debian, Win 2003).
Each of these OSes reside on its own physical harddisk. The boot
is guided by a lilo which assigns the appropriate harddisk
as the boot disk for each OS.
GNAT was installed when the computer was booted as XP. The 
installation was done using the gnat-3.15p-nt.exe installation
program and works fine. The files were copied to C:\GNAT\...
</context>

Now I want to use GNAT when the computer is booted as Win 2003.
The boot disk is E: with environment variable SystemDrive=E:.

I have set following variables in Win 2003:
ADA_INCLUDE_PATH=C:\GNAT\lib\gcc-lib\pentium-mingw32msv\2.8.1\adainclude
ADA_OBJECTS_PATH=C:\GNAT\lib\gcc-lib\pentium-mingw32msv\2.8.1\adalib
Path=C:\GNAT\bin;C:\GNAT\lib\gcc-lib\pentium-mingw32msv\2.8.1;
E:\WINDOWS\system32;E:\WINDOWS;E:\WINDOWS\system32\WBEM;
E:\oracle\product\10.1.0\Db_1\bin;
E:\oracle\product\10.1.0\Db_1\jre\1.4.2\bin\client;
E:\oracle\product\10.1.0\Db_1\jre\1.4.2\bin;

, but I get still an error message (F: is a data partition on the
same physical hard disk as where E: resides):

F:\anders>gnatmake test
gnatbind -x test.ali
gnatlink test.ali
ld: cannot open crt2.o: No such file or directory
gnatlink: cannot call C:\GNAT\bin\gcc.exe
gnatmake: *** link failed.

crt2.o is found in
C:\GNAT\lib\gcc-lib\pentium-mingw32msv\2.8.1 and
gcc.exe is found in C:\GNAT\bin\,
both is in the PATH variable.

Any hints how to proceed?
Maybe Win 2003 access rights on the XP hard disk directories C:\GNAT\
play a role?

TIA
Anders