The setitimer problem of yesterday probably appearently can be worked around by rounding the minimum interval given to be at least 20ms, two clock ticks. We are still testing this.
Meanwhile another strange problem that we were looking at for a few days appears to be resolved. In our PCShare product which contains SMB file sharing we do have a complete netbios naming service. This netbios name service did not properly start up if it is the sole computer in a workgroup. First findings appeared to point to packet length problems, as choosing an odd length netbios machine name made things going (not completely, but it did get further along). Thinking a bit more about that I tried turning off hardware checksumming, and voila, it appears to work fine. The hardware checksumming feature was a recent addition to MacOS X, and appearently depending upon if a broadcast packet is an even or odd number of bytes in size has some weird problems.