WebPlus X7: Tag not closed?

Hi there fellow webplus friends!

I've had someone advise me on the SEO of my website.
They have advised me that...

The page contains invalid mark-up.

The Tag 'a' was not closed correctly, the Tag 'span' was closed instead.

Action:

Analyse the mark-up for errors.

Would anyone be able to help me with this please!?
I have no idea what it means! Let alone how to fix it!! :(

Thank you.
SM:HELP