Using BACKUP_MYSQL_ADMIN_PLUGIN-1.2.0.10a on a Win2k box, I get

Warning Result code: 1
Warning 0 => 'c:/mysql/bin/mysqldump.exe" "--host' is not recognized as an internal or external command,
Warning 1 => operable program or batch file.

Have edited the language file (backup_mysql.php) to:

define('LOCAL_EXE_MYSQL', 'c:/mysql/bin/mysql.exe');
define('LOCAL_EXE_MYSQLDUMP', 'c:/mysql/bin/mysqldump.exe');

However, running it in DOS works, using

c:\mysql\bin\mysqldump.exe my_database -u root -p

Have tried changing / to \ but this gives:

0 => 'c:\mysql\bin\/mysqldump.exe" "--host' is not recognized as an internal or external command,

Any clues? All input appreciated.