Need help installing SCS, please

[Guest TechGremlin]

Hey, guys.

Been playing BGI/II forever (still have the original discs somewhere), but only stumbled across the modding scene over here.

Sadly, I fail to install SCS.

I. I'm using both the Enhanced versions right now.
II. Steam is not installed in stupid directories.
III. I'm failing this on a very average Windows 11 setup.

a. I've run Modmerge and it's done its thing.
b. But I can't install any SCS component. It's giving me this very obvious flag:

Spoiler

FAILURE:
Modmerge is required before mods can be installed on this game. Check the readme for more information and a link to download Modmerge.
Stopping installation because of error.
Stopping installation because of error.
Stopping installation because of error.
Stopping installation because of error.

ERROR Installing [Replace +1 arrows and other projectiles with nonmagical "fine" ones], rolling back to previous state
Unable to Unlink [weidu_external/backup/stratagems/3010/OTHER.3010]: Unix.Unix_error(1, "unlink", "weidu_external/backup/stratagems/3010/OTHER.3010")
[weidu_external/backup/stratagems/3010/UNSETSTR.3010] SET_STRING uninstall info not found
Will uninstall  59 files for [STRATAGEMS/SETUP-STRATAGEMS.TP2] component 3010.
Uninstalled     59 files for [STRATAGEMS/SETUP-STRATAGEMS.TP2] component 3010.
Unable to Unlink [weidu_external/backup/stratagems/3010/READLN.3010]: Unix.Unix_error(20, "unlink", "weidu_external/backup/stratagems/3010/READLN.3010")
Unable to Unlink [weidu_external/backup/stratagems/3010/READLN.3010.TEXT]: Unix.Unix_error(20, "unlink", "weidu_external/backup/stratagems/3010/READLN.3010.TEXT")
ERROR: Failure("Modmerge is required before mods can be installed on this game. Check the readme for more information and a link to download Modmerge.")
Please make a backup of the file: SETUP-STRATAGEMS.DEBUG and look for support at: For help troubleshooting installation problems, go to the Sword Coast Stratagems forum at gibberlings3.net.

c. But I can't rerun Modmerge (because it said already installed).
d. I also tried DLCmerge, but this one also says already installed.

I suppose I'm missing something fundamental here? As I said, I'm a complete noob when it comes to BG modding, but I did have a look at the readmes, and I can't figure this one out.

Help please.