To fix employee salary error messages in BUSY, you can follow these steps:
1. Check the salary structure configuration in the voucher settings.
2. Ensure that the effective date in the structure matches the date you are entering the salary for.
3. Make sure that all the required components, such as Basic, HRA, and DO, are included in the employee salary data.
4. If any components are missing, add them to the salary data.
5. Recalculate the salary with the correct number of days and adjust the presentation date if needed.
6. After recalculating, the salary details should be correct and the error messages should be resolved.