Debian webmin-virtualmin zencart

HP ML380 4GB RAM, dual zeon processor, Raid 5 (6X36GB SCSI drives). I set this server up 4-5 months ago for self hosting. Currently a few affiliate sites (wordpress), Vtiger CRM, etc... all seem to be working ok. I installed ZenCart a few months ago and have been slowly configuring. During checkout we started to get this error: "1062 Duplicate entry '' for key 2 in: [insert into phpbb_users (user_id, username, user_password, user_email, user_regdate) values ('55', 'name', 'e80b5017098950fc58aad83c814978e', '', '1267900305')] I found an article [login to view URL];highlight=phpbb3 ; I backed up the original, renamed the file, dropped the new file in place and tried to do another signup and it crashed. I tried putting the original file back, I manually modified the 2 lines that another article told me to modify. I'm stuck... In addition to fixing this issue with this one virtual server, I would like someone with verifiable experience to go through the entire debian/ virtualmin server and apply best practice and any safe optimization. MUST HAVE VERIFIABLE EXPERIENCE AND SPEAK GOOD ENGLISH!