What I am trying to do is fetch a single list item that has the highest ID, but also has a value in the Shelf field. Below is my query, which I am pretty sure I formatted correctly.
<View>
<Query>
<Where>
<IsNotNull>
<Field RefName='Shelf'/>
</IsNotNull>
</Where>
<OrderBy>
<FieldRef Name='ID' Ascending='False' />
</OrderBy>
</Query>
<RowLimit>1</RowLimit>
</View>
However, when I test the code I get the error
Request failed. One or more field types are not installed properly. Go to the list settings page to delete these fields.
undefined
I am not sure what it is that is going wrong, since I checked that I am using the actual column name, not the display name (which are the same in this case anyway).