Also: mysql5_initial.sql, mysql_initial.sql, mysql_update.sql scripts wont work.
That would be a error on your end, that means you don't have access to the database.
All privileges are given.
===============
User 'webmail'@'localhost' - Database webmail : Edit Privileges
Database-specific privileges
Database Privileges Grant Table-specific privileges
webmail ALL PRIVILEGES No No
===============
C:\Documents and Settings\Administrator>mysql -u webmail -p
Enter password: ************************
mysql> connect webmail
Connection id: 363
Current database: webmail
mysql> source D:\Websites\Server\roundcubemail\SQL\mysql5.initial.sql
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected, 1 warning (0.03 sec)
ERROR 1101 (42000): BLOB/TEXT column 'preferences' can't have a default value
Query OK, 0 rows affected, 1 warning (0.02 sec)
Query OK, 0 rows affected, 1 warning (0.05 sec)
Query OK, 0 rows affected, 1 warning (0.01 sec)
Query OK, 0 rows affected, 1 warning (0.03 sec)
Query OK, 0 rows affected (0.00 sec)
mysql> source D:\Websites\Server\roundcubemail\SQL\mysql.update.sql
ERROR 1091 (42000): Can't DROP 'body'; check that column/key exists
ERROR 1060 (42S21): Duplicate column name 'html_signature'