Error 6004 every time I reopen Pro Tools

[el biciclista]

I have a Mac 867 with digi001/ProTools LE. I also have a Kurzweil K2600, Lucid A/D and D/A converters, a Lucid GenX6 clock, and a Great River preamp. The converters are connected to ProTools vis SP/DIF, and the K2600 is connected vis optical ADAT (8 inputs). I sync ProTools with the clock vis SP/DIF from the A/D.

Whenever I quit ProTools, and then immediately try to go back into ProTools, I get error 6004:

"DAE unable to communicate with the audio hardware".

I have gone through earlier threads re 6004 problems when (1) the computer sleeps or (2) Sound Manager is set to "Digidesign". My problem does not appear to be related to either; the computer does not sleep for this problem to occur and I have Sound Manager set to "Built-in".

To cause the problem when I am in ProTools I just save the open session and close it, quit ProTools, and then immediately double click on the ProTools LE alias on the desktop to go back into ProTools LE. I get error 6004 as ProTools is reloading. To successfully get back into ProTools, I have to restart the computer.

This is not huge problem, but it is a real time waster.

Anybody have a solution to this one?
Thanks!
Mike