For a sales professional, which one is more important - negotiation skills or problem solving skills?

negotiation skills is more important as it will lead to solve the problem... 

i believe that  both of negotiation skills and problems solving skills have same important for a sales professional 

sales professionals should concentrate on problem solving skills and let the negotiations take care of themselves, why ? because clients will find reasons not to go ahead, sometimes known as objections, most of these objections are fake or smokescreens, sometimes however, they are, genuine concerns, if you concentrate on these and make sure the client is happy with the product and your answers to any concerns the business should have a natural conclusion. eg. the client wants the product for a cheaper price, this could be tackled by lower the price and discussing new and lower prices with the client, however, a more sensible approach would be to approach this as a genuine concern, treat all concerns as questions, is this example the question is. show me how affordable and well priced your product/ service is, break it down and demonstrate the value for money.

Depends on what product you are pitching or  selling to clients. As for me i do believe that if a sales person is able to negotiate he will also be able to convince the client for closures in no time. Once the client is convinced then problem solving will not an issue (post sales). Hence it is a step by step method in which both goes hand in hand together. 

Negotiation skills or problem-solving skills?

Both addition to knowing the product ... all of them represent the basis for the work of the seller

Negotiations skills are very important for a sales professional because the would be customer requires lots of convincing to come to your terms which requires negotiation. However both Negotiation skills & problem solving are integrated and a good sales professional will require a blend of the both for post effective sales promotion.

For a Sales Professional Negotiation skills are very important as the customer will be in a position of bargaining and the sales professional should be smart enough where to draw the line understanding his requirement.

We have seen most of the time a guy with good product knowledge will not be able to close the deals bcos of negotiation skills.

Problem solving skills are required by a Customer relation Manager to solve the problem..

Problem Solving is the major tactful skill needed, as now a days customer already already have a set mind of what to buy and prices are no concern as far as the services provided before and after account for the value for money.