Devmon MATH

Is anyone using MATH in devmon templates?? I'm trying to calculate percent memory used for a couple of Windows 2000 servers and I'm getting:

"Error(s) while parsing 'PhysMemUsed' on xxxxxx"

The transforms file contains this:

 PhysMemUsed  : MATH : {PhysMemSize} - {PhysMemFree}
 PhysMemPerc  : MATH : ({PhysMemUsed} / {PhysMemSize}) x 100

and the corresponding OIDS are:

 PhysMemSize   : 1.3.6.1.4.1.232.11.2.13.1.0 : leaf
 PhysMemFree   : 1.3.6.1.4.1.232.11.2.13.2.0 : leaf

If I report PhysMemFree & PhysMemSize in the report message, I get sensible values. For example, right now they show 471 & 1152, so PhysMemUsed would be 681 and PhysMemPerc would be 59%.

I get the above error message, and PhysMemPerc is displayed as "Parent data missing".

Any clues??

Ralph Mitchell