I wrote a program that analyzes a 1.5 GB text (CSV) file and outputs a
3.0 GB text file. However, it turns out that on the 2.3 something
millionth row, it is missing a comma. Therefore, when trying to import
the flat file into SQL Server, it is complaining about data type error.

What i would like to do is to write a VBA program that will just insert
a comma into the appropriate place in the file (I can figure out the
offset that i would like to place it at). If this is not possible
because of the way data is stored on disk, it is also possible for me to
remove a character from elsewhere in the line to make up the
difference. Therefore, what i want to do amounts to changing

20040315,34.349,20020401-45.69,13.34897273,100 into ---
20040315,34.349,20020401,-45.69,13.3489727,100

However, I do not know how to do this. Any help would be appreciated.