SQL backup lock up the database access

[santam2007]

We found some Networker error events for SQL backup as below.

I think the below event will lock up the database access.
Is there any solution for such problem?

Subject: Operations Manager Critical Error Alert on mydomain\mydomain

Severity: Critical Error
Status: New
Source: SQL Server 2005 Service Availability
Name: SQL Server 2005 Block Analysis (MSSQLSERVER.BizTalkDTADb)
Description: The program "EMC NetWorker Module for Microsoft (R) SQL
Server" has been blocked for 2.8328 minutes on database BizTalkDTADb in
the SQL instance MSSQLSERVER. The defined acceptable blocking threshold
is 1 minute(s). "EMC NetWorker Module for Microsoft (R) SQL Server" is
running on SPID 56 as login NT AUTHORITY\SYSTEM and is blocked by SPID
59. The resource id is DB: 9 [BULKOP_BACKUP_DB]
.
Domain: mydomain
Agent: CISED199
Time: 26/03/2007 23:03:02