i assume you are running your programm as a scheduled task ... did you give writing permissions to the target folder for the executing user of the task??
edit:
with permissions you can have 2 scenarios:
- windows authenification
- mixed authentification
if you are using windows authentification, the read and write permissions of the windows user are taken. otherwise the permissions for the sql server service account.
and this behaviour makes sense to me and maybe hits the nail in your scenario!
edit 2:
i don't want to encourage you to do so ... some admins may hate you when you mess up their acl's
but this may do the trick
btw: Magnus Johansson already gave you a "try-this" link
no matter for which method you go - be sure to hand in the correct user (as descriped above!)
(for full history)
...
side-note:
i know this is not the exact answer to your question, but i would recommend you smo to generate backups ...
like
using Microsoft.SqlServer.Management.Smo;
var bdi = new BackupDeviceItem(/* your path inlcuding desired file */);
var backup = new Backup
{
Database = /* name of the database */,
Initialize = true
};
backup.Devices.Add(bdi);
var server = new Server(this.SqlServer);
try
{
backup.SqlBackup(server);
}
catch (Exception ex)
{
// * log or sth
}
you only have to care for the .dll's. take assemblies for the desired server version (some params/properties vary through different server versions)
more info here