I cannot see the code in the edit box, due to you being the current editor -- but, have you tried turning on the enhanced editor function and using it to find your errant ref problem? You might also find it using Ctrl+F.
The most likely culprit is an unclosed starting <ref> -- either with another <ref> instead of </ref>, or a missing </ref>.
Another culprit might be a missing end ref name tag - but, as I said, I cannot see to code to know which.
(A <ref name="whatever" requires an end </ref> - and on subsequent uses the <ref name="whatever" /> should be used with the space before the />.)