gfortran Permission denied

[michael <cs@networkingnewsletter.org.uk>]

I've just installed, without error, gfortran on my AMD64

mkb@amd64:~/work/Fortran$ dpkg -l|grep gfortran
ii  gfortran                          4.1.1-15
The GNU Fortran 95 compiler
ii  gfortran-4.1                      4.1.1-21
The GNU Fortran 95 compiler
ii  libgfortran1                      4.1.1-21
Runtime library for GNU Fortran applications
ii  libgfortran1-dev                  4.1.1-21
GNU Fortran library development
mkb@amd64:~/work/Fortran$ uname -a
Linux amd64 2.6.18-6-amd64 #1 SMP Thu Apr 24 03:57:46 UTC 2008 x86_64
GNU/Linux

and it seems to compile a simple code okay:

mkb@amd64:~/work/Fortran$ cat simple.f90 ; gfortran -o simple.out
simple.f90
program michael
implicit none
write(*,*) 'hi'
write(*,*) index('hi','!')
end program michael

but it won't run!

mkb@amd64:~/work/Fortran$ ./simple.out
-bash: ./simple.out: Permission denied
mkb@amd64:~/work/Fortran$ ls -lt ./simple.out
-rwxr-xr-x 1 mkb mkb 10039 May  7 23:41 ./simple.out*


but it's totally unclear to me what the problem is....

All ideas welcomed, M