kb 893086 and services

Hi Group,

I have a service running on my XP sp2 machine that performs
backupoperations to a samba network.

The service worked fine since installed half a year ago.

The service does backup to a mapped networkdrive (e.g drive H.

It stopped working when update 893086 was installed. That is, at night
it still worked, the update took place about 10.30 am and the next
backup, scheduled at noon showed the error: cannot create directory
H:\backup\xxx.

I tried to uninstall the update, no effect. Still not working.
The service runs under a user-account with local adminstrator privileges.

If I replace the mapped network targetdirectories with UNC-names, it
works again!

A lot of clients use this backupservice and I would like to know:

Could this be related to kb 893086?

tia!

John