IDB Backup getting failed

Hi!!!!!.....

My IDB backup is getting failed and showing following error:-

[Critical] From: DBBDA@xyz001.abc.in "[Database]: dp001"  Time: 8/13/2014 5:50:51 PM

      Velocis server ob2_40:

      (Change log cycle timeout (S_BUTIMEOUT)).

[Critical] From: DBBDA@xyz001.abc.in "[Database]: dp001"  Time: 8/13/2014 5:50:51 PM

      Velocis server ob2_40:

      Backup mode not active

      (backup mode is not active (S_BUNOTACTIVE)).

[Warning] From: DBBDA@xyz001.abc.in "[Database]: dp001"  Time: 8/13/2014 5:50:51 PM

      Cannot un-lock the keystore.

[Major] From: DBBDA@xyz001.abc.in "[Database]: dp001"  Time: 8/13/2014 5:50:51 PM

      ABORTED Database HotBackup Disk Agent on dp001 "[Database]: dp001"

I have to restart backup atleast 4 to 5 times then it runs successfully...

I am facing this issue last two days....

first day i tried to fix this issue by adding OB2DBRETRY=1 in omnirc file but I got the same error on second day...

can anyone suggest me the solution????

DP version is 7.0

thanks in advance....