Bank recon says that other users are logged in to the cash book you are trying to reconcile when nobody is accessing it.
Go to the company folder ad look for any ACCBTN1.000 files. Note the extension of the file must have a number and not dat.
The number in the extension represents the user number in Pastel.
The number in the file name represents the entry type number of where the open batch is captured.
Delete the file applicable to the user that receives the error and the entry type concerned and the error should no longer appear.