My backup  started working there was some lock on the job.

Check the application pool identity in the IIS also the check which id the share pint services is using to start this.

My batch file is in the location c:\Program Files\SharePoint Portal Server\Bin


spsbackup /portal http://hpcepmportal:2001/ /file :\spsdata\FoodPortal\hpcFood.bak /overwrite

I run this from admin login scheduled task.


Also i noticed in your script it is

E:
cd \Program Files\SharePoint Portal Server\Bin

This should be CD c:\Program Files\SharePoint Portal Server\Bin.

I dont know if you orginal script is like this but here you have missed the c:

If you have not missed it then try checking all the stuff i told you before.

Hope yours also start working.