The author while pointing out another mistake writes:

4/162: mukiimiin (feminine plural) should be mukiimuun (masculine plural – see 7/160) [1]

The verse (4:162) is:

لَكِنِ الرَّاسِخُونَ فِي الْعِلْمِ مِنْهُمْ وَالْمُؤْمِنُونَ يُؤْمِنُونَ بِمَا أُنْزِلَ إِلَيْكَ وَمَا أُنْزِلَ مِنْ قَبْلِكَ وَ الْمُقِيمِينَ الصَّلَاةَ وَالْمُؤْتُونَ الزَّكَاةَ وَالْمُؤْمِنُونَ بِاللَّهِ وَالْيَوْمِ الْآخِرِ أُولَئِكَ سَنُؤْتِيهِمْ أَجْرًا عَظِيمًا

The author, again, is committing a mistake that even a 4th grader won’t! He writes that مقيمين (mukiimiin) is feminine plural while a masculine plural مقيمون (mukiimuun) should have been there. This, ironically, is 101% wrong because both مقيمين and مقيمون are masculine plurals! However, one is in nominative case and the other is in accusative case!

Perhaps he wants to say that مقيمين is not in nominative case though it should be. The answer is: it is a common rule of Arabic that if you want to highlight something in the text but don’t want to spend extra words for it then you change it to accusative case. In this verse, المؤتون and المؤمنون are in nominative case but المقیمین has been changed to accusative case to highlight this attribute. Why? Because it demands more importance here. Therefore, the verse should be translated as: ‘especially those who say prayers’ i.e. just by changing مقيمون to مقيمين sense of ‘especially’ has been added. Arabic grammarians call it نصب علي المدح والذم او علی الاختصاص. Hence, this is not a mistake of Quran but a further proof of the sheer ignorance of author!

[1] http://www.1000mistakes.com/1000mistakes/index.php?Page=002_002_001_001 (Retrieved on July 11, 2013)