Hi Xin
There are a couple of things going on here, and I think to fix the first problem first, you should probably check your baseline selections, especially for your Er166 channel. Typically it's when there are selections with no data. You can automatically check for this using iolite's Selection Checker tool.
If your selections are valid, that error message should go away. After that, you can address the "missing metadata" issue. This happens when one of your channels does not have an element defined for it. Each channel now has a property called "Element" associated with it. This is because sometimes channels have names coming from the mass spectrometer like m168 and that could be Er168 or Yb168 (or both). So if the mass spectrometer has not set the Element, you can do this in iolite's Channels Browser. Click on the channels and check for the Element property. If it's not there, you can it by clicking the + button at the bottom of the properties, and adding the element (e.g. "Er") for each channel.
If you have a lot of channels without elements, please let me know and I can show you a way to set them via the python interface to avoid having to do it manually for each channel.
That should fix the errors you're seeing. Please let us know how it goes.
Kind regards,
Bence