"We have been in talks with Celta for the last two days, but the money they want means any deal is unlikely," McCarthy’s agent Rob Moore told planetfootball.com.
"They want £500,000 just to take him on loan, which is too much and is not helpful to Benni at all.
"He wants to move to England and we have got the interest there.
"Benni is not happy with the situation, but he knows what Celta are asking.
"I am not confident a deal will go through, but if the money is paid then something will happen. Benni's wages are not a problem, we already know that and so it is just a matter of this fee."