Just a general rule with error messages: Usually they are not as good as they could be. But never the less read them carefully. Most of the time they tell you what you need to know...
And an other wisdom: Errors are really errors and they have to be solved. Warnings are warnings and you should investigate if they appear. Do not ignore both of them unless you have clearly understood what you are doing.
mysql> SHOW WARNINGS
is often your friend! Further sources to find the problems are: