I think the issue is the MAKE FILE command. TBH, I didn't realize that command even existed, as OPEN TO WRITE creates a file that you can immediately write to, and I have never had to use MAKE FILE. Also, you have a typo when you print (you read the variable into 'fx', but tell it to print 'fix'. The edited version here:
fix=167
fx1=fix
if file exist("fix1.dat")=1 then delete file "fix1.dat"
print " delete file" : wait key
open to write 1,"fix1.dat"
write file 1,fx1
close file 1
print "file fix 1 written": wait key
open to read 1,"fix1.dat"
read file 1, fix
fx2=fix
close file 1
print "fixtures"," ",fx2," ",fix
wait key
So many games to code.....so little time.