Add this to script..
Code:
[Files]
Source: oggdec.exe; DestDir: {tmp}; Flags: dontcopy
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[Code.]
ExtractTemporaryFile('oggdec.exe');
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if not ISExec ( 0, 0, 0, ExpandConstant('{tmp}\oggdec.exe'), ExpandConstant('"{app}\data\sounds\*.ogg"'), ExpandConstant('{tmp}'), '...',false) then break;