If res\php does not have res\php\runtime, then the following error occurs.

1. Validating parameters.
2. Validating Tool's PHP Resource.
   Runtime Exception: 0: PHP Runtime within Tool's PHP Resource is invalid!

Error: Unexpected Exit

 
However, this error is not necessary, if provided source already contains a php folder.
 
Resolution:
If source does not have PHP folder, then check if tool has PHP runtime within \res\php\runtime.
If source does have PHP folder, then checking if \res\php\runtime exists is ignored.