Hi,
The error clearly explains that the vendor master 2526 is not created. If you have tried to create vendor, please go to SE16 and check the tables LFA1 and LFM1 and ensure that the vendor 2526 exists in the table. If the vendor exists in LFA1 and LFM1, the error wont be triggered in me11 while creating info record. You may check the the transaction MK02 and check whether you are able to edit the vendor 2526. Please check and revert back.
Regards,
AKPT