Escalation Not Being Applied

Hi, hope someone can help as I have to have this working by Sunday night...

In the past I've had escalations working as I'd expected - there doesn't really seem to be a lot to go wrong as far as I can see. However, on returning to a K2 solution after some time of not being involved with it, I'm finding that none of my escalations are working at all. I've no idea when they stopped working - only that they used to, but right now they aren't.

(Bear in mind - I'm under a heap of pressure here, so it could be that I am forgetting / missing something blindingly obvious - I'm sure it wouldn't be the first time!)

EXAMPLE:

I have an activity with a number of events on it which I want to escalate from if nothing's happened within a certain time. To test it, I'm giving it 3 minutes though in reality it would be n number of days.

The Escalation Rule looks like this: (I've tried both Use GUI and Use Code)

public void Main(EscalationRuleContext K2)
{
int Days = 0;
int Hours = 0;
int Minutes = 3;
int Seconds = 0;

K2.SetEscalationRule(Days, Hours, Minutes, Seconds,0);
}

The Escalation Activity I've tried as both Expire, and GoTo - the latter going to a step in the workflow which is below the current activity, linked with a line rule that evaluates 1=0 (i.e. always False, as I only want to go there from the escalation).

Whenever I run the process and get to the Activity in question, it just sits there with the first user-based event on it showing as active / available in worklists. It never seems to escalate, expire, move on to the 'GoTo' activity, etc. - even though well over 3 minutes have elapsed.

I've checked Errors in K2 server - nothing there. (I once tried deliberately putting a bug in the Escalation Rule code like an int.Parse("rubbish") - this showed up as an error, so the rule is obviously being executed.)

Running the Server interactively just shows No Clarification.Rule: Completed - (the name of my escalation). It then goes on to execute the events in the activity - it completes the first one as this is all server based, then sets the second one to 'Active' - and that's as far as I get.

Any help much appreciated!