I’m assuming that _the number of ways the votes can be cast_ treats the experts as well as the candidates as distinguishable, so that there are $5$ different ways in which Candidate A can receive $4$ votes and Candidate B only $1$ vote (assuming that neither A nor B is the candidate against whom one expert has a grudge). If only the vote tally matters, then you want Arturo’s answer.
The selector with the grudge can cast his vote in $3$ ways. Each of the other four experts can cast his vote in $4$ ways. The total number of ways in which they can cast their votes is therefore ... ?