You are getting this error because you have the Value column of one of your entries in the IniFile table has more than 255 characters in it. Since Value is a formatted type you can instead create a Property table entry for this data and then refer to the Property from the value Column. The Value column of the property table does not have a limit to the number of characters you can enter, so this error would go away.
So in the Property table:
Property = MY_PROPERTY_NAME
Value = Some really long string
And in the IniFile Table:
Value = [MY_PROPERTY_NAME]