EM17 Error

Hi, I am working on R12.1.1 and I am getting the EM17 error while transferring journal entries to GL from AR. Can anyone suggest a solution please?

its a sequencing error have

its a sequencing error have you created any new GL source /category...have u created sequence for that you can either set Sequential Numbering Profile Option to Partially Used on the Site Level or Assign seq to all the new document types