Backup Schedule Stops after 12 am-Dbacockpit

Hi Guys,

I am having strange issue on my server.

System:BW

OS:Windows 2008    

Database :Sybase ASE 15.7

I have schedule the automatic full backup let say 6.30 pm after business hours  and transaction log every hour which I have scheduled at 6.45 Pm .The full backup and transaction log backup works fine every hour but after 12 am ,the transaction log stops that means the last backup will be till 11.45 pm .I don't find any log information in Dbacockpit as well as in ASE.log.

Any suggestion or any one has gone with same kind of issue.

Thanks

Asim