Opalis Integration Server imposes a default limit of 50 concurrent policy instances running on a single Action Server in order to prevent depletion of the Windows resource known as Desktop Heap which causes unexpected execution results such as process terminations and inability to allocate necessary resources to perform just about any kind of task.
Error messages returned or exceptions captured in Action Server or Policy Module logs include "Out of memory", "Not enough storage" and other messages that make reference to an inability to allocate a resource such as a Named Pipe or Windows Socket.
To continue reading see the following KB article:
KB2102398 - How to increase the maximum number of concurrent policy instances running on a single Opalis Integration Server Action Server
J.C. Hornbeck | System Center Knowledge Engineer