When taking multiple concurrent connections (SMP machine), php interprets scripts very wrongly.

I can reproduce this easily by hitting the server with a web browser while benchmarking with apachebench.
(ab -n 50 -c 3 http://host/large-script.php)

Instead of the proper results, I get these error messages:

1)
PHP has encountered an Access Violation at 016CCEFA
Warning: Nesting level too deep - recursive dependency? in
d:\include\global.pi on line 34

(line 34 is the function declaration of a simple debug function included in a global header specified in registry Per Directory Values auto_prepend_file.)

34: 
function DebugComment($sz){
  // Conditionally display debug message if we have debugging enabled.

  global $aDebug;

  if ($aDebug)
    printf("<!-- %s -->\n",$sz);
}