In ISE 11.2, Project Navigator added the ability to specify a project working directory other than the main project directory.
If a user chooses to specify an optional working directory and then copies the project to a new location with a different working directory, Behavioral Simulation might error out with he following message.
ERROR: no Simulation Engine found in the Transform Input that matches testbench_isim_beh.exe
Process "Simulate Behavioral Model" failed