The documents were prepared to take loan against a pretended a purchase; that is to say that nothing was purchased and there was no intention to purchase anything but to take loan and use it for other transactions in the business. Are the salaries for that particular month of the people involved in this transaction haram?

If this is against the rules, then it is not allowed.
With regard to the salary, if the bank is private, he have to return part of the salary which falls against such action, while if it is partially owned be the government, then this part should be paid to poor people.