Comments by Matthias Adloff (Top 1 by date)

Not only that you forgot to mention the -not completely obvious- additions that mendy pointed out, your solution will stop working after the first file name replacement.
If you have saved your first replacement (2) file, it will then look for
- fileCount 0 => exists
- fileCount 1 => does not exist so write (2).

The correct solution is to leave the fileCount + 1 away.