The blank page suggests that PHP has hit a fatal error. Enabling error reporting in your php.ini file (either to the screen or to a file) should help determine what is going on.

Since we use PEAR DB/MDB2 to connect to a database one of these packages must be installed for the db support to work properly.  MDB2 is the recommended package as it is actively developed but either the DB or MDB2 PEAR package will work.

The problem you are having could be because these packages are missing from your PHP install.

Hope that helps,
Jason