Exec() and Windows 2000 SP1

I have tried running the PHP funciton exec() on a Microsoft Windows 2000 (5.00.2195 Service Pack 1) box and it does not run. The cmd.exe process loads but just sits there, as if it either crashed quietly or is still waiting for something (like it doesn't know how to process the request). The same code runs fine on Windows Millenium Edition (4.90.3000). Does anyone have any ideas as to what's causing this? Is it a discrepancy between PHP calling command.com on Windows 9x and NT calling its closest equivalent cmd.exe? Better yet, how do I get around calling an external program from PHP in an NT box and get it to execute? Philip J. Murphy Charlotte, NC