If I attempt to run a simulation with ModelSim from the PlanAhead tool, the following error occurs:
"ERROR:[Runs-112] Failed to locate the ModelSim 'vsim" executable program in the shell environment 'PATH' variable. Please source the settings script included with the installation and retry this operation again."
Note that the ModelSim executables are in the $PATH variable.
The PlanAhead 14.2 tool was corrected to properly locate vsim when the executable is found in the PATH.
ModelSim can be used in standalone mode when using the PlanAhead 14.1 or earlier tool versions, or you can use ISE Simulator from within the PlanAhead GUI.