As per Microsoft:
Explanation: A static packet filter could not be created. System configuration might be incorrect, and the service might have attempted to create the filter for an external remote host on an ISA Server internal interface, due to incorrect configuration for default routing. Otherwise, memory resources might be low.
User Action: For system configuration problems, check the Local Address Table (LAT) configuration, run ipconfig/all to check TCP/IP configuration, and run Route -Print to obtain a list of registered, persistent routes. To check the LAT, in the ISA Management console tree, click Servers and Arrays, click Name, click Network Configuration, and then click Local Address Table. For low memory resources, close other applications or stop and restart the services.