1) After setting required parameters and clicking “Create Scheduled Backup” in the command prompt I was getting the following error:  ERROR: Invalid starttime value.
Well, actually the format of the date as it was created was wrong. Possibly just because of the regional Options… The server’s regional options where I run SharePoint site is Italian. So, to go around this I just copied the generated SCHTASK command and modified the time value:

Original command was like this:

D:\>SCHTASKS /create /sc DAILY /mo 1 /tn "Catapult SharePoint Autobackup" /tr "C:\SharePoint Utils\sushi.exe -autostart:Catapult_SharePoint_Autobackup" /s \\WSSSERVERNAME /st 01.00 /F /u DOMAIN\UserName ERROR: Invalid starttime value.

I made it look like this in a Notepad:

SCHTASKS /create /sc DAILY /mo 1 /tn "Catapult SharePoint Autobackup" /tr "C:\SharePoint Utils\sushi.exe -autostart:Catapult_SharePoint_Autobackup" /s \\WSSSERVERNAME /st 18:30 /F /u /RU DOMAIN\UserName /RP password

After running this command in a command prompt window the tasks was successfully created. However, there I have encountered another problem to resolve as described in point 2.

2) When I tried to Run the scheduled task the I got the following error:

"Catapult SharePoint Autobackup.job" (SharePoint) 2/4/2010 8:48:00 AM ** ERROR **
    Unable to start task.
    The specific error is:
    0×80070005: Access is denied.
    Try using the Task page Browse button to locate the application.

Searching Internet led me to Microsoft’s KB article related to this error, however in my case the error was due to the ‘space’ character in the folder path: “D:\SharePoint Utils\sushi.exe“. Simply renaming the folder name and modifying the task with correct path resolved this problem.

Hope this information will help someone who has encountered the same problem.