This means as it is in the message , you have posted an entry missing a mandatory dimension code,
Solution to that
1- developer to codeunit and update the missing journals dimensions values
2- if developer is not avaliable and as it is a currency valuation , all you have to do is to set the dimension code as not mandatory change the option field to be blank , this will allow you to make your revaluation after that set the dimension to it is defualt