Problem editing units_tables

[Royal28]

Hello,
I am trying to create a new unit and I am in the process of following this great tutorial here.
I have followed all the steps, but while I was trying to edit units_tables\my_units, i cloned and edited a line for my custom unit - washington_battalion - and when I attempted to save it, I got the following error: Object cannot be cast from DBNull to other types
I discovered that when I tried to save ANY new line in this table, I received this same error.
What do I need to do to fix this problem?
Thanks,
Royal28 [IMG]file:///C:/Users/Connor/Desktop/Misc/Capture.PNG[/IMG]

[gunde]

This is an error you get when a column has no data in it. Wherever you create a new row and get this error, just click continue and check if any column is empty. Fill in data and try to save again. In units_tables it's probably the MP_Cost_Late column.