Incremental Backup fails after one execution

Dear forum members

My version of Acronis: Acronis Backup & Recovery 10 Agent (Build 10.0.13762)
My system: Windows Small Buisness Server 2011 Standard SP1 x64

I have the following problem: Each time I run an incremental backup job, the first execution is succesfull.
When the job tries to run the second time, it fails. Then I have to empty the destination folder of the backup to make the backup run again.

When i edit the job after one execution, the level of the roll-back periode changes to two instead of 6 or 7 and the roll-back periode is loading and loading.

I have this problem on more than one server. I tried to change the folder, making new jobs and restarting the services but the problem is still there.

In the attachement you can see the problem.

Did anyone else before had this problem?

Thanks for your answers.

Sincerely CFU