Fortran output large array to netCDF nf90_enddef

Hi first question on stackoverflow.

I've been stuck on this for 5 days. I want to write a netcdf file in Fortran.

I'm using netcdf/3.6.3 I am trying to output a large 43000x 18000 array named frech and some smaller ones (1d arrays).

a sample of my code is below it is a really large file and the problem is not in putting in values for the variables the problem is ending the definition of variables:

  print*,"nunks is",nunks
  print*,"neqns is",neqns


  ok=nf90_create('michalek.nc', NF90_CLOBBER, ncid)
  print *,"create ok=",ok

  ok=   nf90_def_dim(ncid,"nunks", nunks, nunks_dimid)
  print *,"def nunks dimension ",ok
  ok=   nf90_def_dim(ncid,"neqns", neqns, neqns_dimid)
  print *,"def neqns dimension ",ok
  dimids=(/neqns_dimid, nunks_dimid/)
  print *,dimids
  ok=   nf90_def_var(ncid,"frech", NF90_REAL, dimids, frech_varid)
  print *,"def frech",ok
  ok=   nf90_def_var(ncid,"src", NF90_REAL, nunks_dimid, src_varid)
  print *,"def src",ok
  ok=   nf90_def_var(ncid,"csrc", NF90_REAL, nunks_dimid, csrc_varid)
  print *,"define csrc",ok
  ok=   nf90_def_var(ncid,"dat", NF90_REAL, neqns_dimid, dat_varid)
  print *,"define dat",ok
  ok=   nf90_def_var(ncid,"cdat", NF90_REAL, neqns_dimid, cdat_varid)
  print *,"define cdat",ok
  ok=   nf90_enddef(ncid)
  print *,"end dif ", ok
  ok=   nf90_put_var(ncid, frech_varid, frech)
  print *, 'frech put in ok=',ok
  ok=   nf90_put_var(ncid, src_varid, src)
  print *, 'src put in ok=',ok
  ok=   nf90_put_var(ncid, csrc_varid, csrc)
  print *, 'csrc put in ok=',ok
  ok=   nf90_put_var(ncid, dat_varid, dat)
  print *, 'dat put in ok=',ok
  ok=   nf90_put_var(ncid, cdat_varid, cdat)
  print *, 'cdat put in ok=',ok
  ok=   nf90_close(ncid)
  print *, 'close?',ok

I understand that ok=0 when the file is correctly read However when I get to the stage of ending the defintions of the file (nf90_enddif) ok is returned as =-62 and the netcdf file is not created. I imagine its a problem with a too large array but I can't fix this problem

the relevant output for the above code is:

nunks is       43894
neqns is       18144
create ok=           0
def nunks dimension            0
def neqns dimension            0
     2           1
def frech           0
def src           0
define csrc           0
define dat           0
define cdat           0
end dif          -62
frech put in ok=         -39
src put in ok=         -39
csrc put in ok=         -39
dat put in ok=         -39
cdat put in ok=         -39
close?         -62

Thanks for any help!

Regards Peter :)