Problem solved. Something is wrong with my MODI 12.0 and I also messed with the OCR method parameters. Changing the line:

$miDoc->OCR();
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to

$miDoc->OCR(2052,1,1); #2052 is the LangId for Chinese
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can solve the problem but somehow if I use

$miDoc->OCR(9,1,1); #9 is the LangId for English
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Windows XP would throw me an error saying:

unknown software exception
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Anyway, thank you guys! I'm really happy that the problem is gone :D