most likely you have problems having access to MySQL via PHP.
The steps myDBR takes during install are:
1) Checks that the database connection is ok
2) Checks if mydbr-database exists and if does not, offers to create one or lets user manually create one.
3) Checks if valid myDBR-objects exists in the mydbr-database and offers to create those or lets user manually create them.
Do you get any of these or does the error happen as soon as you enter your database info?
The error you are seeing is not normal and happens when myDBR database and it's objects are being created. There is something in the environment that causes problems.
Couple of things you should try:
1) Check that your setup allows connection to database:
Edit the file in mydbr/tools/troubleshoot/mysql.php and try to access it (http://localhost....)
2) If the database connection works ok, try the manual installation.