problem resolvedby (no login)
I did cut out the format statement (528). In the end I resolved the problem by removing write statements one by one (for the particular unit) until the problem went away. I did find one write statement which seemed to cause the problem. The syntax of the statement is OK and when run alone (as you did, there is not problem).
Apparently this write statement along with the logic of the program causes the binary file to be created. I did not think that this could be.
The bottom line is that the problem was resolved, but I am aware of the specific reason for its occurance.
Thanks for all of your assistance.