Yeah, it seems they made a change so that you can only query channels that are not disabled by other channels. For example, the reflection rays channel is disabled (greyed out) when the reflection amount is 0, in which case it will give that popup error. Actually, the render current view script that is included with modo also runs into this problem, but it executes OK.
Anyway, I went through and fixed this in IrradianceXSR, you just have to search through the various functions and add some if statements to check if transparency amount, reflection amount and subsurface amount are nonzero before trying to query dependent channels. It's the same three lines pasted in all the sampling and basic preset functions right before the relevant queries.
if lx.eval('item.channel advancedMaterial$reflAmt ?') > 0:
if lx.eval('item.channel advancedMaterial$tranAmt ?') > 0:
if subsamt > 0: