general photoshop error translating layer

I'm trying to translate a duplicated layer in the ExtendScript Toolkit, but I'm getting a "General Photoshop error occurred.  This functionality may not be available in this version of photoshop."  I'm running CS6 and just calling the translate function. 

I've tried calling it in a variety of ways including what seems to have worked for others, but I get that error every time. 

layer.translate(new UnitValue("200 px"), new UnitValue("200 px"));

OR

layer.translate(new UnitValue(200, "px"), new UnitValue(200, "px"))

Am I calling this incorrectly or can the layer be in a state that's not able to translate?  I'm trying to bias and scale a layer so a given rectangle in it becomes the full size of the image.