Hi Andrey,
Is there any difference between the problematic machine and other mahcines that don't have such a problem(e.gCPU, OS version, memory and etc)?
If you don't use the Infragistics in your application, does this problem still exist on the problematic machine?
Is it possible that other programs running on the problematic machine affect your application? You may have a try stopping other programs running on the machine to see if it helps.
Linda