I compared your file with the original, but I really didn't see anything obviously wrong. However I did notice two things:

1. On Page 7 your missing the hidden fields for page three (under html_record_form).

2. Under html_modify_success you have the following step commented out:

if ($in{'PageStatus'} eq "1") {print qq|<meta http-equiv = refresh content = "0; URL=$db_script_link_url&modify_form=1&PageStatus=2&ID=$in{'ID'}">|;}

Not sure if that could be the cause or not. Nothing else really jumped out at me... let me know what happens.