error FOR3309: undefined label 124 - fortran

Question

I wrote this but when I try to build *.exe say:
Compiling Fortran...
C:\Users\LORD\Desktop\TText1.f90
C:\Users\LORD\Desktop\TText1.f90(197): error FOR3309: undefined label 124
Error executing fl32.exe.
This is the source code of the project:
program one
real::x(6),f(6),deltaf1(6),deltaf2(6),deltaf3(6),deltaf4(6),deltaf5(6)
real::gradf1(6),gradf2(6),gradf3(6),gradf4(6),gradf5(6)
real::h,x1,x2,s1,s2,p1,p2,Y1,Y2
real::Z,T,a,b,c,d
open(unit=16,file="E:\N\xi.txt")
open(unit=148,file="E:\N\fi.txt")
gradf1(:)=0.0
gradf2(:)=0.0
gradf3(:)=0.0
gradf4(:)=0.0
gradf5(:)=0.0
deltaf1(:)=0.0
deltaf2(:)=0.0
deltaf3(:)=0.0
deltaf4(:)=0.0
deltaf5(:)=0.0
do i=0,5
read(16,*)x(i)
read(148,*)f(i)
write(*,12)x(i),f(i)
12 format(2F12.4)
end do
do i=0,4
deltaf1(i)=f(i+1)-f(i)
end do
do i=0,3
deltaf2(i)=deltaf1(i+1)-deltaf1(i)
end do
do i=0,2
deltaf3(i)=deltaf2(i+1)-deltaf2(i)
end do
do i=0,1
deltaf4(i)=deltaf3(i+1)-deltaf3(i)
write(*,*)deltaf4(i)
end do
deltaf5(5)=deltaf4(1)-deltaf4(0)
write(*,*)deltaf5(5)
do i=1,5
gradf1(i)=f(i)-f(i-1)
write(*,55)gradf1(i)
55 format(F12.4)
end do
do i=2,5
gradf2(i)=gradf1(i)-gradf1(i-1)
write(*,65)gradf2(i)
65 format(F12.4)
end do
do i=3,5
gradf3(i)=gradf2(i)-gradf2(i-1)
end do
do i=4,5
gradf4(i)=gradf3(i)-gradf3(i-1)
write(*,124)gradf4(i)
end do
gradf5(5)=gradf4(5)-gradf4(4)
write(*,155)gradf5(5)
155 format(F12.4)
h=x(1)-x(0)
x1=0.5
s1=(x1-x(0))/h
write(*,33)s1
33 format(F12.4)
!p(x)=fi(0)+s*deltafi1(0)+(1/2)*s*(s-1)*deltafi2(0)+(1/6)*s*(s-1)*(s-2)*deltafi3(0)+(1/24)*s*(s-1)*(s-2)*(s-3)*deltafi4(0)+(1/120)*s*(s-1)*(s-2)*(s-3)*(s-4)*deltafi5(0)
p1=f(0)+s1*deltaf1(0)+(1/2)*s1*(s1-1)*deltaf2(0)+(1/6)*s1*(s1-1)*(s1-2)*deltaf3(0)+(1/24)*s1*(s1-1)*(s1-2)*(s1-3)*deltaf4(0)+(1/120)*s1*(s1-1)*(s1-2)*(s1-3)*(s1-4)*deltaf5(0)
write(*,*)" vaghti x1=0.5 chand jomleie pishro barabar ast ba=",p1
x2=0.45
s2=(x2-x(0))/h
p2=f(0)+s2*deltaf1(0)+(1/2)*s2*(s2-1)*deltaf2(0)+(1/6)*s2*(s2-1)*(s2-2)*deltaf3(0)+(1/24)*s2*(s2-1)*(s2-2)*(s2-3)*deltaf4(0)+(1/120)*s2*(s2-1)*(s2-2)*(s2-3)*(s2-4)*deltaf5(0)
write(*,*)"vaghti x2=0.45 chand jomleie pishro barabar ast ba=",p2
!Y(x)=fi(5)+s*gradfi1(5)+(1/2)*s*(s+1)*gradfi2(5)+(1/6)*s*(s+1)*(s+2)*gradfi3(5)+(1/24)*s*(s+1)*(s+2)*(s+3)*gradfi4(5)+(1/120)*s*(s+1)*(s+2)*(s+3)*(s+4)*gradfi5(5)
Y1=f(5)+s1*gradf1(5)+(1/2)*s1*(s1+1)*gradf2(5)+(1/6)*s1*(s1+1)*(s1+2)*gradf3(5)+(1/24)*s1*(s1+1)*(s1+2)*(s1+3)*gradf4(5)+(1/120)*s1*(s1+1)*(s1+2)*(s1+3)*(s1+4)*gradf5(5)
write(*,*)"vaghti x1=0.5 chand jomleie pishro barabar ast ba=",Y1
Y2=f(5)+s2*gradf1(5)+(1/2)*s2*(s2+1)*gradf2(5)+(1/6)*s2*(s2+1)*(s2+2)*gradf3(5)+(1/24)*s2*(s2+1)*(s2+2)*(s2+3)*gradf4(5)+(1/120)*s2*(s2+1)*(s2+2)*(s2+3)*(s2+4)*gradf5(5)
write(*,*)"vaghti x2=0.45 chand jomleie pasro barabar ast ba=",Y2
T=abs(p1-Y1)
Z=abs(p2-Y2)
write(*,*)"tafazole chand jomleie pishro va pasro baraye x1=0.5 barabar ast ba=",T
write(*,*)"tafazole chand jomleie pishro va pasro baraye x2=0.45 barabar ast ba=",Z
! tabe W ra be in shekl benvis=exp(2*x)
!W=exp(2*x)
W1=exp(2*x1)
W2=exp(2*x2)
a=abs(p1-W1)
b=abs(p2-W2)
c=abs(Y1-W1)
d=abs(Y2-W2)
write(*,*)"tafazole chand jomleie pishro va tabe W mord nazar dr noghte x1=0.5 mishavad=",a
write(*,*)"tafazole chand jomleie pishro va tabe W mord nazar dr noghte x2=0.45 mishavad=",b
write(*,*)"tafazole chand jomleie pasro va tabe W mord nazar dr noghte x1=0.5 mishavad=",c
write(*,*)"tafazole chand jomleie pasro va tabe W mord nazar dr noghte x2=0.45 mishavad=",d
stop
end program one

Answer 1

I could say that the problem is that you're using Microsoft Fortran PowerStation, that was discontinued in 1997, but...
You have the line:
write(*,124)gradf4(i)
That 124 is supposed to be the label of a format, but you have no format labeled 124. You do have a format labeled 12 - maybe that's what is wanted.
Here's what a modern compiler might tell you:
t.f90(105): error #6052: This label has not been defined as a FORMAT label. [124]
write(*,124)gradf4(i)
------------^