The ISArcExtract.dll error (often paired with ISDone.dll) usually happens because the installer can't find or extract game files from compressed archives. This is common with "repacks" (like FitGirl or RG Mechanics) where high compression is used. Quick Fixes (Try These First)
folder to ensure no old, corrupted extraction files interfere. Move the Installer: install isarcextract.dll
regsvr32 isarcextract.dll
In the black window, type the following command and hit Enter:regsvr32 isarcextract.dll The ISArcExtract