Which field is it saying is missing on reload? If it is one of the fields in the Section Access spreadsheet then that table will not load and effectively there will be no Section Access.
Section Access is very picky about field names. It is good practice to ensure that all field names and values appear in upper case; with IBNRCLS2 and LIAB it would appear you have this covered.
Not sure what you mean by a 'subfield under the field'. Is this a comma separated list or something? If so, you will need to split the values out into an associated table and do the section access on this.
The fact you are using Personal Edition should not have a bearing on whether Section Access works or not.
One last thing on Section Access, be aware you can lock yourself out of your own document. I would recommend reading this: