The model skin is mixing up when I try to rig:

[Anonymous]

I am trying to animate the rig but when I move arm rig model body get mix. Below is the video for further clarification.
https://imgur.com/a/Oy7Xa0r
Now I am following this tutorial:
https://www.youtube.com/watch?v=YrFi7OvG_xU
In this tutorial guy has used heat solve from weight solver property now the problem is I am working on 3DS MAX 2009 version and 2009 version does not have heat solve tool, and I am unable to find the solution to solve this issue. I have search over the internet to solve this issue but most of the solution are present for new version like this Autodesk help
https://knowledge.autodesk.com/support/3ds-max/getting-started/caas/CloudHelp/cloudhelp/2018/ENU/3DS...

Any solution or guidance will be appreciated for old version of 3DS MAX 2009.