Error in SQL Server 2000

I have installed JIRA (2.6.1 Trial) Standalone on Windows 2000 professional

Tomcat(built in): 4.1.29
JDK: 1.4.2.04
Database: SQL Server 2000

It succeeded in initializing and populating the database. But when i using it, there was an error with message:

>>>Error in creating GenricValue: [SQL][SQL Server 2000]Underlying input stream returned zero bytes.

And i can't create, search, backup...............................

I have re-installed jira and db several times....

Can anybody help me? Thanks very much