The contract they have with SM Entertainment is a contract of 13 years. It will be even more than that, because there will be a pauze when the boys have to go to the army. Junsu, Yoochun and Jaejoong wanted to change some things in their contracts, because the contracts are not fair (and even inhuman). Basically, SME gets 80% of everything they sell and the members get 20% which has to be divided by 5 (members). So 4% each of everything they sell. They also weren't allowed to do solo works outside DBSK. Junsu, Yoochun and Jaejoong invested in a company called CreBeau and SME used it against them. So another reason for the members to want to change the contract. But SME didn't listen to them and didn't change the contracts. So the 3 members decided to start a lawsuit against SME to get the changes legally (they can't leave SME without paying a very large sum of money). It was decided that they can do solo works outside DBSK, but the rest is still undecided. The lawsuit is at a 'halt' now, because they are investigating SME (books aka money, other contracts, ...). After that the lawsuit will continue.
I hope they find something against SME, so DBSK can win
No really, SME didn't want to give the documents in for the lawsuit investigation, so I can only guess that there was something that wasn't looking good for SME. I support the boys in this. It is really an unfair contract and they deserve better than that.
I guess BoA has a contract for 13 years too, since she is celebrating her 10th anniversary in Korea this year. They got everything out of her and pushed her to perform in Japan and America. America failed, she lost popularity in Japan and she hasn't released anything in Korea for years. I really hope her comeback in Korea goes well.