GFortran for 64-bit PC

["Norbert" <npittner at cox dot net>]

Hi,
Recently I bought a new desktop PC (HP6654y, Athlon II processor, 64-bit, 
with Windows 7) and downloaded
the free GCC-GNU GFortran compiler for it, from 
http://quatramaran.ens.fr/~coudert/gfortran/   ,
following instructions to the letter. After 'doing' Fortran for nearly 50 
years (!!), I still have a
lot of stuff I need to do with it every day.
The first dozen or so programs I tried out on this GFortran (= Fortran 2003) 
were 'small' (around 1200
ASCII characters each) and worked perfectly: they compiled, linked, 
executed, and ran (linked) just fine.
All that was needed was the command 'gfortran -o xyz.f', where xyz is the 
name of my source code file.
But the Fortran programs I really need to run are about twenty times larger 
(25000 ASCII characters each)
than those dozen trial balloons above. The big programs will compile OK (no 
syntax or logic errors etc),
but they will not run. My GFortran gives me runtime errors like 
'c:\Users\mememe\AppData\Local\Temp\
ccM8j0Ey.o: xyz.f:.text+0x360a): undefined reference to '_array_' ', were 
mememe is my administrator name,
xyz is the source module again, and array is the name I gave to a 
dimensioned character array in that
ASCII source file; there is also a message 'Collect2; Id returned 1 exit 
status'.
Next I experimented with inserting various link parameter combinations after 
the -o in the above gfortran
command, such as -Wextra or -Wall or -O2 or -g or -static or -march 
or -libgfortran etc, all to no avail.
(I am not a 'professional developer'.)
(By the way, Gfortran, along with mingwm10.dll etc etc resides in my 
ProgramFiles(x86) folder.)
I get the impression that gfortran wants some C+ modules (?), or runtime 
libraries, or 'binaries' (?)
like maybe MinGW or Cypwin or whatever. It just will not TELL me what I 
need, where to get it, and into
which folders on my PC to put them. It's nerve wracking!
Please help.
Thank you.
'Max'