I think the deck is stacked against you. :-)

There appears to be an error in the scripting guide. I think this is the syntax you're looking for:

app.project.renderQueue.item(1).logType = LogType.ERRORS_AND_PER_FRAME_INFO;

It seems to work, but the type doesn't change in the RQ window - but if you open the drop down, you'll see that "Plus Per Frame Info" is selected. Please report back if it does (or doesn't) work for you.

Dan