I don't know the particular problem with your "large BF" file. The only things I could think of are:

- Wrong spelling of the file name.
- Wrong letter-case of the file name.
- Wrong permissions on the file.
- Did not delete the original file before uploading it.
- Drives not set drives back to read-only after sending file to the player, resulting in loss or corruption of the file.

Regarding the "fixed" version with the Win98-compatible dialog box... Please upload it to the file section of RioCar.Org and then I will link it from the FAQ after it is approved.