A government source confirmed that Jordan will oppose the Palestinian decision to go to the General Assembly of the United Nations to declare a Palestinian state unilaterally in September.I think that the last paragraph means that if Israel closes off the border with "Palestine" then it will become Jordan's problem to give them jobs, currency and so forth, a responsibility that Jordan does not want.
The source added that Jordan's national interest would be hurt if the Palestinian National Authority declared a state, particularly with regard to issues of refugees, water, Jerusalem and borders.
The source said that the unilateral declaration of a Palestinian state is in the Israeli interest because Israel is interested in the establishment of a Palestinian state "within the boundaries of the separation wall" and this means there is a limit to the Palestinian state with Jordan, which was rejected by Jordan in the final.
UPDATE: YNet has it in English with more details.