Well I'm not sure what "common suggestions" you have tried, so I'll just list some stuff to try to fix and if it doesnt work just reply back & lmk.
1 - Make sure you are logged into windows on an acct with admin privileges
2 - Make sure you are running both D3 & DB as admin (Right click each, properties, check Run As Administrator)
3 - If you are running an antivirus, malware, and/or firewall program, make sure you add your Demonbuddy folder to the exclusions list in each of those programs you are running.
4 - (If step3 applied) - The easiest step is just to re-run the demonbuddy installer. (Because some of those programs, especially norton, will remove some of the necessary demonbuddy files thinking they are malicious.) - Of course the other option to that is to go into the program and mark file as safe and do a restore of the files removed... Easier just to add your db folder to exclusion list and rerun installer though.. That way you are sure you get everything installed back.
5 - Perform a fresh DB install using the latest DB build.
6 - Make sure you are using the EXE demonbuddy installer (not the zip) .. Sometimes using the ZIP, windows will block the exe from running correctly.
7 - Did you try the DB Install Wizard? (Link to that on signature bar)
Post back, lmk if you get it running.. Goodluck!