Same thing happened with me and a mod I was testing out. In your product manager, you have drop down options next to each mod... Edit the mod and remove the conflicting SQL query from the uninstall code. In this case it'll be this code:
Code:
SELECT COUNT(*) AS users
FROM user AS user, userfield AS userfield
Once you yank that out of there, remove it normally - you may have to repeat the process for removing other conflicting SQL queries, though.