I think it's not an error, it's more like a indication that the latest work experience is not 5 yrs, I experienced the same, I submitted and ignore the message.
1- i think the point will go down on further draws in the future.
2- Primary candidate only for MPNP EOI, EE later on will have the IELTS score considered for the spouse, if you will be going via EE stream
3 - read this...