If you get this error when you try to run runonce.bat:

sireg.exe – System Error
The program can’t start because Crosswalk_2-11.5.64.dll is missing
from your computer. Try reinstalling the program to fix this problem.

it’s probably because your PATH environment variable is missing the Softimage Common Files:

• C:\Program Files (x86)\Common Files\Softimage;
• C:\Program Files\Common Files\Softimage;