I was making some testing by recording a relatively long
single stereo take (about 4 minutes), and then added a
couple of mono tracks. When I tried to play the entire
work, it began to make some strange sounds after 2 minutes.

If I stopped and began the playback near the nasty point,
it does well, so the file itself isn't corrupt.

If I ask the program to mix to preview, it also does that
well.

Any ideas?

I'm running a 350 Mhz Pentium II MMX with 64Mb of ECC RAM,
6Gb Seagate Medalist HDD, Windows 95 with DirectX 6.1
installed. The souncard (YAMAHA DS-XG included with the
Intel motherboard) has the newest drivers, validated for
DirectX 6.1.

Thank you, folks.