I assume that you are using a version of Inno Setup other than Unicode. Machines in which the installer has the wrong encoding probably do not have the Russian set as an obsolete (non-Unicode) encoding.
In the Windows XP Control Panel, select the Regional and Language Options check box. On the Advanced tab, check the box next to "Language for non-Unicode programs." It may be a different language than the Windows interface language. If I am right, working machines have this set in Russian, and non-working machines have this set in English (or other).
In any case, always use the Unicode version of Inno Setup , and you will not have such problems.
No one should develop applications other than Unicode in the 21st century!
Martin Prikryl Oct 11 '16 at 11:46 on 2016-10-11 11:46
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