Full SQLBACKUP using PowerShell fails on $backup.SQLBackup()

Hi

I am logged on to one of the live app servers ( as this has SQL Management studio)

I am trying back up one of the active db server  instances

## Full + Log Backup of MS SQL Server databases/span>            
## with SMO.            
[void][System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.ConnectionInfo');            
[void][System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.Management.Sdk.Sfc');            
[void][System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMO');            
# Requiered for SQL Server 2008 (SMO 10.0).            
[void][System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMOExtended');            
$Server = "SP2010Instance";     # SQL Server Instance.            
$Dest = "y:\";    # shared drive.            
$srv = New-Object Microsoft.SqlServer.Management.Smo.Server $Server;  

Write-Output $srv.Name; 
         
# If missing set default backup directory.            
If ($Dest -eq "")            
{ $Dest = $server.Settings.BackupDirectory + "\" };            
Write-Output ("Started at: " + (Get-Date -format yyyy-MM-dd-HH:mm:ss));            
# Full-backup for every database            
foreach ($db in $srv.Databases)            
{   
    Write-Output $db.Name.          
    If($db.Name -ne "tempdb")  # Non need to backup TempDB            
    {            
        $timestamp = Get-Date -format yyyy-MM-dd-HH-mm-ss;            
        $backup = New-Object ("Microsoft.SqlServer.Management.Smo.Backup");            
        $backup.Action = "Database";            
        $backup.Database = $db.Name;            
        $backup.Devices.AddDevice($Dest + $db.Name + "_full_" + $timestamp + ".bak", "File");            
        $backup.BackupSetDescription = "Full backup of " + $db.Name + " " + $timestamp;            
        $backup.Incremental = 0;            
        # Starting full backup process.            
        $backup.SqlBackup($srv);     
        # For db with recovery mode <> simple: Log backup.            
        If ($db.RecoveryModel -ne 3)            
        {            
            $timestamp = Get-Date -format yyyy-MM-dd-HH-mm-ss;            
            $backup = New-Object ("Microsoft.SqlServer.Management.Smo.Backup");            
            $backup.Action = "Log";            
            $backup.Database = $db.Name;            
            $backup.Devices.AddDevice($Dest + $db.Name + "_log_" + $timestamp + ".trn", "File");            
            $backup.BackupSetDescription = "Log backup of " + $db.Name + " " + $timestamp;            
            #Specify that the log must be truncated after the backup is complete.            
            $backup.LogTruncation = "Truncate";
            # Starting log backup process            
            $backup.SqlBackup($srv);            
        };            
    };            
};            
Write-Output ("Finished at: " + (Get-Date -format  yyyy-MM-dd-HH:mm:ss));

The script seems to list each (sharePoint ) database but then gives up!!!!!!
StateService_6e9ed1bd62e6471abe38f92fe145e98e
.
Exception calling "SqlBackup" with "1" argument(s): "Backup failed for Server '
SP2010DB01M'. "
At E:\daniel\backup_alldbs.ps1:32 char:26
+         $backup.SqlBackup <<<< ($srv);
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DotNetMethodException

Exception calling "SqlBackup" with "1" argument(s): "Backup failed for Server '