Probebly you use gridview:true? I recommend you don't use afterInsertRow anytime. Instead of that you can do any changes in jqGeid inside of loadComplete event. You can use getDataIDs to get IDs of all rows from the jqGrid and make all changes which you need. The parameter gridview:true is good to use. Another way is usage of the custom formatter and custom unfrmatter. This way can allow you to produce any cell contain in the jqGris.

Best regards
Oleg