displaying memory available OID on Windows Servers in percentage

Hi,

Please give me advice  step by step how to display memory available OID on Windows Servers in percentage? I know there is transform option for that. I have pasted below code to Tranform field: Event->Event_Classes->Classes->Perf/CPU->Transform

import re

match = re.search('threshold of Free Memory [^:]+: current value ([\d\.]+)', evt.message)

if match and device:

    avail = float(match.groups()[0]) * 1024

    total = device.hw.totalMemory

    percent_used = (1 - (avail / total)) * 100

    evt.summary = "Memory threshold exceeded: current value %3.1f%%" % (percent_used)

but it doesn't work at all. What is the problem?

Oli