Seeking G77 Fortran Help

[R.C. Cooper]

Greetings GNU Contact,

I am running GNU 77 Fortran which I downloaded earlier this year.  I am
creating all files using Notepad.

I am having some difficulty getting a compiled program to run.  I have
narrowed it down to the subroutine that needs the in.dat (data file),
which is opened in a prior subroutine within the main program, to
assign variables quantities.

I think that there is a problem with the format statements .. I don't
really understand if / in a Format statement merely ends a line, or if
it also sends the 'carriage' to the next line?

the in.dat file contains
"
  in.dat for problem 1
00002          IB
00006          IE
00001          IDTYP: 1=RECTANG. DUCT, 2=2D-DUCT, 3=AXISYMMETRIC DUCT
+1.00000E-01   DI (m): length of control volumes.
"

A prior subroutine, successfully conducts the following:
"
      IDATI=71
      OPEN(IDATI,FILE='in.dat')
"

The call satement from main.f is
      CALL INPUT(IB,IE,IDTYP,DI)

Input.f contains the following associated lines of code:
"
      READ(IDATI,5000) IB,IE,IGTYP,DI
 5000 FORMAT(/I5/I5/I5/E12.5)
"
Everything compiles but on running 'main.exe', I get the following
error message:
"
fmt: read unexpected character
apparent state: unit 72 named out.dat
last format: (/,I5,/,I5,/,I5,/,E12.5)
lately reading sequential formatted external IO

abnormal program termination
"

Hoping that you can shed some light, or point me in the right direction
.. is my formatting line not in sinc with my in.dat file? 

I am at my wits end, even have a course instructor involved who is also
at a loss.

Hoping that you can shed some light on this situation, given your
expertise with GNU 77.

Sincerely,

Ruth

***********************************************************
Ruth C. Cooper, P. Eng
M.A.Sc Candidate - Civil Engineering
http://www.eng.mcmaster.ca/civil/studentpages/cooper.htm
***********************************************************