Looking at that, it problably won't.
The biggest question really is how much should you care about validation.
I know that it's the best to have everything validate, and be sematicly correct so that it all looks grat to the uber-nerds out there that like ot police these things for their own amusment. It also can make a small (tiny) difference to osme search engines depending on the severity of the issue.
I think that the bigest issue is - does it look right on the screen and does it do what it's suppsoed to? If the answer is "yes" to both of those, I do tend to discount a 100% validation sometimes. The other thing is that unless you have access to that plugin, or can get the devloper to listen to you, there's no real way of "fixing" it yourself. you can fix the issues in the pluign, but as soon as there's an update, any changes that you make will be over-written anyway.