I had exact same problem. Here's what I learned and how I fixed my system.
- When the modpack has been successfully installed the directory \res_mods\configs\xvm\Aslain does NOT contain the file PATCH.EXE
- When my install failed it produced the error shown below (from the installer - not from anti-virus) when it found that PATCH.EXE was already there,
- AND because the permissions were fouled up the installer could not move/delete/whatever it needed to do with that file.
I fixed my system by the following
* Restart system
* Log in as administrator or account with administrator privileges
* Delete the entire directory \res_mods\configs\xvm\Aslain
* Perform another install of latest modpack being sure to select option to "Delete all previous mods from the game"
Summary
- At some point during a previous modpack install, something went wrong which caused the installation to either malfunction or finish prematurely.
- The result of that occurrence was a corrupted file system in the aforementioned directory, where the permissions were broken and files remained that should not.
- Prior to this issue I had not received any indication of any modpack install not being successful.
- I have NO IDEA what actually caused the corruption, but my game works fine now .