Error 7865 - The amount in [EMPLOYEESCONTRIBUTIONSONALLEARNINGS] must be 0.00

One of our employees has reach retirement age part of the way into the last month of the tax year (March). We have changed the NI letter to C and have a new tax code for them. When we go to submit to HMRC it says ["The amount in [EMPLOYEESCONTRIBUTIONSONALLEARNINGS] must be 0.00 if the [NILETTER] is 'X', 'C', 'K', 'S' or 'W'. Please check", '7865', "This must be 0.00 if [NILETTER] is 'X', 'C', 'K', 'S' or 'W'.", 'Diagnostic message:', 'Assertion failure:'] The amount that the PAYE Basic software calculated is £40.30 for the employee to pay in NI. Surely the software should have calculated it correctly. Is there any way of changing the figure to be 0?

Hi,
Unfortunately we do not have access to your records on this forum. For assistance you would need to contact the online helpdesk: 
Technical support with HMRC online services 
Thank you.
Thank you.

Thank you for the reply. Spoke to technical support at HMRC and got the issues sorted out. They were very helpful.