Need to include the files in the script too like:
[Files]
Source: "Include\arc.ini"; DestDir: "{tmp}"; Flags: dontcopy
Source: "Include\CLS.ini"; DestDir: "{tmp}"; Flags: dontcopy
Source: "Include\English.ini"; DestDir: "{tmp}"; Flags: dontcopy
Source: "Include\Facompress.dll"; DestDir: "{tmp}"; Flags: dontcopy
Source: "Include\unarc.dll"; DestDir: "{tmp}"; Flags: dontcopy
and under CurStepChanged procedure too:
ExtractTemporaryFile('arc.ini');
ExtractTemporaryFile('CLS.ini');
ExtractTemporaryFile('English.ini');
ExtractTemporaryFile('Facompress.dll');
ExtractTemporaryFile('unarc.dll');
If these don't help, check if your arc.ini has zlib definition like:
[External compressor:xtool]
header = 0
unpackcmd = xtool.exe decode -t100p - - <stdin> <stdout>
If you want, you can also try out this and directly use the Setup.dll file from DSG.
Simple Installer FMXInno
Compile it with Inno 5.6.0