Error Dumping MSSQL database

[Voland]

Hello!

Trying to create domain backup from Plesk CP to local repository
After "Done" message from Plesk getting such kind of email.

Backup process has completed for domain "xxxxxxxx"
The following warnings were encountered during backing up:
Unable to create dump file for MS-SQL database xxxxxxx on domain xxxxxxxx

I tried several accounts but result same.

Server: IBM 3250
OS: Windows 2003 standart edition (All updates) .NET 3.5 Latest.
CP: Plesk 8.3
MSSQL: 2 instances, MSDE, SQLExpress 2005
HDD: 50% used