Drives go missing when using dvdbitset

I have a wierd problem when running dvdbitet. I have 2 80GB physical drives, each one split into 2 partitions. i.e. c: and d: on drive 1, e: and f: on drive 2. When dvdbitset is running e: and f: disapear leaving just c: and e: This is a problem when source material for writing to dvd is on one of the ‘invisible’ drives.

Both drives are SATA and the BTC is primary on the 1st IDE channel.

I’ts not new in this forum.
I have the same problem with all versions < V049.

I am using ver 050. Bitsetting works fine, i just can’t use half my drives when using it.