After installation process verify files permissions (not for Windows systems):
-rw-r-----(chmod 640) for files
drwxr-x---(chmod 750) for directories
Some hosting services require more provileges on files and directories (found on RedHat AS).
If you have errors on permissions try to use 644 (HAAARR!!!) for files where was 640
and 755 (HAAARR!!!^2) for directories where was 750.
If you can create a specific user for SUMO database it would be better thing. So, change default user and password
to connect to it (see your database manual for details).
Remember to set correct database user and password in <sumo_dir>/configs/config.database.php.