Sql Server Express 2005 9.0.2047 - Problem RESTORE VERIFYONLY FROM DISK

Hi all

every time I try to verify the backup file I get the error:

backup set on file '1' is not valid (translated from italian).

this is my backup script:

BACKUP DATABASE [ahr_sistema] TO DISK = N'C:ProgrammiMicrosoft SQL ServerMSSQL.1MSSQLBackupahr_sistemaahr_sistema_backup_1.bak' WITH FORMAT, INIT, NAME = N'ahr_sistema-Completo Database Backup', SKIP, NOREWIND, NOUNLOAD, STATS = 10

GO

declare @backupSetId as int

select @backupSetId = position from msdb..backupset where database_name=N'ahr_sistema' and backup_set_id=(select max(backup_set_id) from msdb..backupset where database_name=N'ahr_sistema' )

if @backupSetId is null begin raiserror(N'Verifica non riuscita. Impossibile trovare le informazioni di backup per il database ''ahr_sistema''.', 16, 1) end

RESTORE VERIFYONLY FROM DISK = N'C:ProgrammiMicrosoft SQL ServerMSSQL.1MSSQLBackupahr_sistemaahr_sistema_backup_1.bak' WITH FILE = @backupSetId, NOUNLOAD, NOREWIND

GO