MKDIR is a regular WeiDU action.
I'm getting the same error message on my system (Windows 7). Executing this script:
BACKUP ~test/backup~
AUTHOR ~Argent77~
BEGIN ~Test component~
PRINT ~My documents folder is "%USER_DIRECTORY%".~
MKDIR ~%USER_DIRECTORY%/1~
produces the following result:
[D:\Games\Baldur's Gate II Enhanced Edition\Data\00783\setup-test.exe] WeiDU version 23600
Using lang\en_us/dialog.tlk
Install Component [Test component]?
nstall, or [N]ot Install or [Q]uit? i
Installing [Test component]
My documents folder is "C:\Users\argent77\Documents/Baldur's Gate II - Enhanced Edition".
Creating 1 directory
Problem Unix.Unix_error(1, "mkdir", "C:") on C:: util.ml
SUCCESSFULLY INSTALLED Test component
Press ENTER to exit.
The folder has been created however, and the mod appears to be installed successfully.
Edit:
Only access to drive C: (regardless of path) is affected on my system. MKDIR works fine on all of my other drives. Correction: After further testing it looks like the error message is displayed whenever the path is pointing to a drive that is different from the game's path. For example, paths pointing to drive C: or E: are causing errors if setup-xxx.exe is executed somewhere on drive D:.